EP1121974B1 - Mixing apparatus and use - Google Patents

Description

The invention relates to a device for mixing flowable substances, in particular by dispersing and emulsifying, according to the preamble of claim 1, as well as the use of such a device according to claim 6.

In process engineering, the general purpose of producing desired end products is based on a formulation-based quantitative ratio. For example, for the mixing of pasty masses and emulsions, especially with droplet sizes in the micron range, it may be advantageous if two or more reagents are brought together in the mixing process in other proportions to the conclusion of the desired product in terms of mixing time, total amount and temperature to optimize. In particular, when a large amount of a first reagent is to be combined with a smaller amount of a second reagent, thermodynamic and flow processes may render appropriate or even necessary a different process regime.

Among the reasons for deviating quantity approaches called DE 20 04 143 A1 in that in the preparation of suspensions or emulsions with small particle sizes, a short residence time is required to prevent so-called Oswald ripening, ie the growth of large particles at the expense of the smaller ones due to re-dissolution. In crystal growth, by adding a phase, supersaturation is achieved which causes the Germ number per unit volume determined; after nucleation has begun, the addition of further solutions predominantly contributes to the growth of the already formed nuclei or crystals, which reduces the number of microunits formed overall. This is stated in the cited document and similar in US 2,641,453 derived the technical teaching to merge two phases over a coaxial pipe route. However, inevitably a temperature equalization occurs. However, such heat exchange prior to mixing may be highly undesirable for some processes.

DE-C-639 769 describes a device with a vertical container for mixing, emulsifying, homogenizing etc. of substances. In one design, a centrifuge located under the bottom of the container drives the mix through narrow channels in and through a homogenizer - with a horizontal drive shaft for a rotor / stator system - up where it circulates in the container, from where it returns to the underlying rotor becomes. Heavy material flowing down the tank and lighter material from the upper tank area are mixed, crushed and finally pumped out in the rotor / stator system. For fine and finest distribution of sensitive substances, this device is hardly.

Loud DE-A1-198 29 646 and a brochure "Becomix DUO Homogenizer" is, for example, for producing aqueous solutions of alkyl ether sulfates, in a container with a similar homogenizer as described above, a first product flowing axially to the stator with a second product supplied from the rotor side only between the teeth of the rotor / Stator unit mixed. This is designed so that a high shear and clockwise intensive pumping is achieved in the clockwise.

In DE-U-296 08 713 is described a dispersing whose rotor / stator system between specially shaped teeth has channels that act as a shear gap and are alternately released and covered during rotor circulation. When changing the axial distance between the rotor and stator, the gap volume increases or decreases disproportionately. This can be flowable material, eg a pasty mass, even.

Between two different modes of operation - namely in-line and circulation mode - can be a mixing and homogenizing according to EP-A2-0 036 067 switch, which has at the bottom of a container, a rotor / stator system, wherein an axially adjustable ring each opens a channel and blocks a second channel. The mix is always pressed radially from the inside to the outside by the dispersing sprockets, and you can either circulate the dispersed material through an external bypass or dissipate.

With a homogenizer after EP-A1-0 769 254 At the bottom of a container, a rotor / stator system is present, which is overlapped by a spring-loaded sealing ring. With open valves, the mix is circulated via a circulation line. By closing the valves, the sealing ring is raised with increasing pressure, so that a return is released into the container. The rotational energy of the rotor is preferably converted into the highest possible pumping action, also to avoid additional pumps for the spray cleaning.

It is an object of the present invention to achieve, in an economical manner, an optimum mixture of stirring substances, especially of those reagents which, at least initially, have to be tempered at different temperatures or at all have different temperature behavior. For this purpose, a further development of known mixing methods in conjunction with dispersers is sought, which in particular have a coaxially toothed rotor / stator arrangement. Permanently reliable means of production in the construction should be as simple as possible, producible and mountable with minimal effort, and convenient and trouble-free to use, and without sacrificing product quality. In terms of environmental protection and cost savings, energy consumption must be minimized, both in batch mode and generally in the continuous process.

Main features of the invention are specified in claims 1 and 6. Embodiments are the subject of claims 2 to 5.

The invention relates to apparatus for homogenizing substances and / or for producing emulsions with droplet sizes in the micron range, with a disperser disposed on a container, with at least one rotor / stator system near the container bottom, wherein the disperser, a rotor, a stator comprising an intake port, a product supply from above, and a bottom flange having an intake port with a supply conduit, and wherein the stator has an outer stator ring with outer stator teeth and radial passages and an inner stator Stator ring having inner stator teeth and radial passages, and wherein the stator outside the outer stator ring defines a deflection chamber, wherein the inner and outer stator teeth are aligned axially from top to bottom, and wherein the rotor has axially upwardly oriented sprockets. According to the invention, it is provided that the rotor has an underside facing the bottom flange, wherein the outer stator teeth overlap the rotor at a peripheral edge contactlessly with minimal distance, protrude to the bottom flange, and correspond with a downwardly directed tooth edge of the rotor periodically aligned channels are formed between the deflection chamber and a premixing chamber upon rotation of the rotor, wherein the rotor, the stator and the bottom flange of the disperser limit the premixing chamber between the bottom of the rotor, the stator outer stator ring and the disperser bottom flange, the rotor -Unterseite has a reaching to the region of the pre-chamber flat cone and at least one cone-shaped or concave outer surface with a steeper cone or Zentriwinkel, wherein the distance between the underside of the rotor and the bottom flange is formed radially from the inside to the outside, and wherein the inlet channel opens below the rotor in the premixing chamber.

With this device, a two-stage dispersing process is feasible, in which one diverts a partial stream from a main stream of a reagent I coming from the container and supplies a second partial stream (side stream) to a mixture with a reagent II which is produced in the premixing chamber, whereupon the mixture of the two partial streams is conveyed through the rotary-driven disperser into the remaining main stream. This process is extremely economical and highly effective. Quantitative small partial flows can be adjusted easily and with very low inertia as needed, most simply by means of a metering pump. The partial flow technique also offers the advantage that the concentration of the addition reagent only has to have the ratio based on the partial flow. This also applies to the otherwise often difficult phase emulsion emulsification in the hot / cold process.

In very fast throughput to achieve a uniform distribution even with problematic products by intensifying the mixing by pulsation in a ring or outlet channel, preferably with cyclic pressure buildup and - degradation in the antechamber. In particular, by dosing the partial flows and optionally by changing the speed of the disperser can control the volume and pressure conditions. This makes it possible to process reagents with different temperatures and in different concentrations. Dispersers known per se may be used with a coaxially nested rotor / stator system in which shearing forces between densely adjacent concentric tooth baskets, at least one of which is rotationally driven, homogenize passing mix discharged through periodically aligned channels; Depending on their geometry and dimensioning, different velocity components and turbulences occur at the shear gap. However, a cascade arrangement of two dispersing devices with different working volumes is also suitable, provided that the throughput in the premixing chamber of the second disperser can be controlled.

Cyclic pressure differences on such a disperser support the rapid and uniform distribution of the reagents by, in phases of high pressure, reagent I being conveyed into the premixing chamber, which uniformly disperses under pulsation in respectively subsequent phases of lower pressure with the reagent II under turbulence in the antechamber. Mixing therefore proceeds optimally in terms of process engineering, regardless of the proportions to be set for the end product. In the pre-mixing chamber, thanks to an extremely short residence time of e.g. Only 5 ms only a minimal heat exchange instead, so that a hot-fed reagent II cools very little, while it is thoroughly mixed with the reagent I.

An important feature of the invention is that mainstream and substreams receive different energy densities, which contributes significantly to optimal dispersion and emulsion formation with the smallest possible particle or droplet sizes. Specifically, an energy density can be imparted to the mixture of the partial flows in the premixing chamber, which is considerably higher, for example by at least one order of magnitude, than the energy density in the main flow. Unless one deviates without the introduction of high specific energies, for example, to induce a desired chemical reaction, one obtains after all a strong homogenization, which supports this process. For example, subtleties below 0.5 microns can be achieved easily. In non-Newtonian fluids, the increase in energy as it flows into the premix chamber occurs in the Generally, a viscosity reduction takes place, which significantly improves the mixing with low-viscosity substances.

It is advantageous if the energy density and residence time in the partial flow, i. the volume and time related energy input is variable, in particular by such a setting that a leading to an emulsion envelope critical energy density is not achieved, which is very important, for example, for the production of mayonnaise, dressing sauces, etc.

When using a separate dispersing this is continuously fed only with that part of the main stream of RI, in the premixing chamber, the reagent R II is metered in the amount corresponding to the total amount, whereby one reaches in the outlet flow of the dispersing an over-concentration of R II, whereupon The over-concentrated mixture (R I + II) is processed in a small-sized high-pressure homogenizer and mixed with the remaining reagent RI '. Compared to the prior art, the required effort is significantly reduced. Nevertheless, you can achieve high-quality end products in an extremely efficient way.

In a mixing zone, preferably given by the premixing chamber, the mixture (R I + II) is adjusted in terms of temperature and proportion without being subjected to significant shear stress, followed by a high shear area provided by the rotor / stator system, in particular at long tooth edge of the rotor. The adjusted partial flow method goes above all with this embodiment, far beyond the conventional technology. It can be developed so that from the reagents, a phase mixture is produced by different speeds and different static pressures in the premixing chamber, wherein a phase I is conveyed directly into the latter and a phase II passes through pulsation due to cyclic pressure differences via inlet channels in the premixing chamber.

For homogenizing substances, eg pasty masses, and / or for producing emulsions with droplet sizes in the μm range, using a disperser arranged in or on a container with at least one rotor / stator system, in particular near the container bottom, and optionally with Promoters for a carrier stream, the invention provides a two-stage generation and mixing of defined partial flows by producing a precursor in a first process step from a reagent or wax solution and adding this to the carrier stream in a second process step. The term wax is in the context of the present invention for all substances which are solid at room temperature and liquid or flowable at elevated temperature, for example, also fats, paraffins, esters and the like. A major advantage of the novel process control is that the carrier substance does not have to be brought to the melt-melting temperature but can retain room temperature. The resulting product still has a very high degree of homogeneity, because the droplet size can be controlled by adjusting the energy density according to the product; It therefore meets all quality requirements.

A hot reagent stream (by-pass stream) is combined in the first process step with a metered from the main stream of the cold carrier substream and dispersed - introducing the necessary energy for droplet size - whereupon the mixture to produce the final product in the second process step with the remaining part of the carrier Mainstream is mixed. The optimization of the volume ratio of carrier substream to precursor substream significantly reduces the number of product cycles; after only one revolution, the desired concentration of reagent II in reagent I can be reached. For example, a processing time of only 15 minutes for 2,000 kg of cream is readily achievable. Agglomerate formation, as in Oswald ripening, does not occur here because the amount of emulsion needed to take up the wax addition is small and thus appreciable cooling is avoided. The wax can be incorporated at high energy density in the carrier without streaking. The fineness of the particles is decisively supported by the energy input in the rotor / stator system, in which the increase of the surface energy is applied or exceeded by a multiple. During the then shock-like cooling of the large volume of the main stream of cold carrier substance, the wax particles harden, which prevents secondary agglomeration. This achieves a homogeneous particle size distribution and thus a significantly improved product behavior.

Very advantageous is a measure according to which the method is designed to be self-dosing by the hot below the rotor / stator arrangement supplied reagent partial stream (side stream) dispersed in a premixing chamber with a first partial stream of the carrier and the resulting precursor via a return is diluted with the main stream flowing from above and mixed to a final stream. It is advantageous if in the premixing chamber, a reverse Trombe is generated, the negative pressure contributes to the metering of the reagent substream or side stream. When the rotor is running at high speeds, circumferential velocities of more than 20 m / s may occur in the rotor / stator system, so that the medium present in the premixing chamber is strongly forced outward through the disperser owing to strong centrifugal acceleration, thereby experiencing an increase in energy.

The mixing of partial and main flow can be assisted by controlling the static pressures, wherein in particular in the second partial flow a static pressure is generated which exceeds that of the main flow. This can be achieved surprisingly well, that the premixing chamber associated with the lower and radially outer parts of the rotor and the precursor is initially deflected from there to the outside, before accelerating it on the stator top and the radially further inside flowing main stream supplies. The pressure is expediently set by sizing and selecting the ratio of the inlet / outlet cross sections.

In contrast to the known dispersing systems, in which mixing and shearing are carried out simultaneously in the region of the greatest shear gradient, the present method separates mixing and shearing in time as well as locally. Thanks to the introduction into the premixing chamber, an optimum emulsion can be produced by introducing a homogeneous phase mixture. In contrast, in known dispersing equipment, a considerable part of the highest shear range is used for mixing. The product passed through the rotor / stator system may be conveyed as a discharge stream to another vessel in which the product is kept homogeneous, e.g. by means of a slow-running agitator. This saves energy and further counteracts Oswald ripening.

If one requires powder constituents for the end product, it can be provided that they can be mixed with the main stream from above, so that they are taken up in the material stream at high speed and rapidly swirled.

An embodiment of the invention further relates to a arranged in the upper region of the device conveying member, for performing the method. Farther it can be provided that the premixing chamber is flow-connected via an outlet channel with a space at the bottom of the rotor / stator assembly.

Thanks to such a Vordispergierkammer, which requires very little space, the device of the invention is energetically extremely advantageous. It represents a substantial development of facilities, for example according to DE 296 08 712 U1 represent, the stator and / or rotor approaches with - seen in cross-section or settlement - have trapezoidal or trapezoidal shape, ie wedge structures that significantly influence the flow due to different surface portions and Abreißkanten. Also against a dispersing loud DE 296 08 713 U1 , which brings about disproportionate changes in the shear gap volume by adjusting the axial distance between the stator and rotor, the invention achieves a considerable acceleration of the dispersion with the installation of a premixing chamber.

The premixing chamber is disposed in the outer region of the rotor between its lower side and the limiting housing side so as to extend from the center of the rotor lower side to a premixing chamber outlet. With minimal space requirements, this pre-chamber is optimally accommodated in this way on the rotor / stator system. In this case, the outer stator ring on downwardly projecting stator teeth, which overlap the rotor circumference with a minimum distance contactless and extend to one of the rotor underside centrically opposite bottom flange. This design causes or at least increases the generation of increased static pressure in the premix chamber. The latter is thereby limited to a small volume, in which an intensive predispersion - for example of supplied hot reagent - without annoying cooling is going on.

Conveniently, the supply line terminates in a e.g. oblique inlet channel, which is integrated as a ground-parallel radial channel relative to the outer rotor bottom in the bottom flange. It is possible to construct the construction so that the rotor has a maximum diameter at its upper side and from an outer peripheral surface to the rotor underside from a peripheral edge or rounding, while the rotor upper side is flat or concave.

A very intensive radial promotion of the medium is effected by the fact that at the rotor underside a deflecting body from a reaching to the region of the antechamber flat cone with at least one cone-shaped or concave Outside surface is formed with a steeper cone or central angle, wherein the transition between adjacent deflection surfaces is preferably designed as a sharp tear-off edge in order to achieve additional turbulence. Thus, at least two bevelled and / or curved surfaces adjoining each other at an obtuse angle can peripherally enclose a step surface of the rotor hub and have steeper angles to the outside. These deflection surfaces conduct the partial flow particularly effectively into the main space. The vigorous centrifugal flow on the outer stator ring therefore already has an axially parallel component which most effectively assists the partial flow entry into the main space.

A preferred design has a stator with a hood which defines, outside the outer stator ring, a deflection chamber which is provided near the bottom flange with circumferentially spaced outlet openings, the conveying member being located immediately above the centrally formed in the hood inlet near the rotor sitting. This extremely compact arrangement can be flanged directly onto a tank bottom and ensures a high degree of homogenization due to the recirculation in a small space.

Dispersers are typically manufactured to very tight tolerances and precisely assembled. In particular, given the small minimum distances in the axially adjustable rotor / stator system, which can be up to 0.1 mm, designed as a hollow shaft motor drive is extremely useful, which is mounted on the bottom flange and on a rectangular support flange is. Thus, the non-positively inserted in the hollow shaft drive shaft remains dimensionally stable in operation, the rotor shaft is preferably axially supported by stops and disc springs within a mechanical seal so that a longitudinal expansion of the hollow shaft and thus the drive shaft only in the direction away from the bottom flange is possible. As a result, heat effects are reliably compensated in a surprisingly simple manner, resulting from the underlying engine. Although the temperatures of the drive shaft in continuous operation, for example, can reach up to 120 ° C, as a result, take place at the disperser above virtually no thermal expansion; rather, upon heating, unavoidable linear expansion of the hollow shaft of the motor occurs solely in the direction leading away from the dispersing device. Therefore, thanks to the consistently narrow gaps on the rotor / stator system, one always has optimum shearing action. To set a Pulsationsseffekts the pressure distribution in the disperser is controllable outlet side, preferably by selecting the flow path and the Umschlingungswinkels or in the outlet behind the outlet port or by the area design and the arrangement of the outlet openings, so that an adaptation to operating conditions relatively simple way can be made.

According to a further development, an attachment which can be flanged to the container bottom has an inlet pipe enclosing the conveying member, as a result of which the medium is sucked in particularly vigorously. From an outlet nozzle goes off a line, e.g. is switchable via a valve and leads back to or in the upper part of the container, if desired, with such a tangent angle that a product rotation generated by the stirring or conveying member is decelerated. Air trapping is avoided when the line is returned below the minimum level of product in the vessel.

The return line can at least partially outside the container, which in a laboratory design, e.g. 16 l and industrially e.g. 10,000 I can hold, installed and tempered as needed. At high dispersing powers, for example in the range from 30 to 50 kW, the novel possibility of external cooling is of great advantage.

A further reduction of the droplet sizes is achieved in that one or both stages of the disperser can be acted upon by ultrasound, for which the rotor forms an intermittent reflector. The rotor teeth rotating past the stator teeth thus effect an intermittent continuous homogenization in the product.

Significantly, a further development, according to which the passage volume in the premixing chamber or its volume itself can be adjusted or changed by changing the rotor shape and / or the stator shape with unchanged shear edge length. If the stator openings are changed in the second stage (with the apparatus otherwise being the same), the shear gradient and thus the volume-related energy are influenced, while the shearing edge of the stator teeth delimiting the premixing chamber remains the same. Conversely, for the purpose of influencing partial flow energy density and residence time, the shearing edge length can be set or changed with an unchanged premixing chamber volume. With relatively simple apparatus means can be so achieve an optimal adaptation of the process management to the respective asked mixing task.

As an alternative to the aforementioned integrated designs, the device can be designed as a separately attachable predispersing stage, especially for the economical retrofitting of existing homogenizing or dispersing plants. Such a separate dispersing device is continuously charged only with that portion of the main stream to which the reagent R II is metered in the premixing chamber in an amount corresponding to the total flow RI, thereby achieving an excess concentration of R II in the outlet stream of the dispersing device. The over-concentrated mixture can be processed through a considerably smaller sized high pressure homogenizer and then remixed with the remaining reagent stream RI '.

Fig. 1

ein schematisierter Prozessbehälter in Axialschnittansicht mit einer angeflanschten Dispergiereinrichtung,

Fig. 2

ein Strömungs-Fließbild,

Fig. 3

eine Teil-Schnittansicht einer Rotor/Stator-Anordnung mit einer Vormischkammer,

Fig. 4

einen vergrößerten Ausschnitt entsprechend dem Bereich IV in Fig. 3,

Fig. 5

eine Axialschnittansicht eines Homogenisators mit schematisch angedeutetem Antrieb,

Fig. 6

eine Axialschnittansicht eines ähnlichen Homogenisators mit einem Aufsatz,

Fig. 7a, 7b, 7c

Axialschnittansichten verschieden ausgebildeter Teile eines Aufsatzes nach Fig. 6, teilweise in auseinandergezogener Darstellung (Fig. 7a),

Fig. 8a, 8b

je eine Draufsicht bzw. Seitenansicht, teilweise im Schnitt, von Statorringen,

Fig. 9a, 9b

je eine Draufsicht bzw. Seitenansicht, teilweise im Schnitt, von Statorringen,

Fig. 10a, 10b

Seitenansichten einer Antriebswelle sowie einer mit ihr kuppelbaren Rührwelle und

Fig. 11a, 11b, 11c

je eine Draufsicht bzw. Seitenansicht eines Rotors und eines Ansatzes.

Further features, details and advantages of the invention will become apparent from the wording of the claims and from the following description of exemplary embodiments with reference to the drawings. Show:

Fig. 1

a schematic process container in axial section view with a flanged disperser,

Fig. 2

a flow diagram,

Fig. 3

a partial sectional view of a rotor / stator assembly with a premixing chamber,

Fig. 4

an enlarged section corresponding to the area IV in Fig. 3 .

Fig. 5

an axial sectional view of a homogenizer with schematically indicated drive,

Fig. 6

an axial sectional view of a similar homogenizer with an essay,

Fig. 7a, 7b, 7c

Axial sectional views of various trained parts of an essay after Fig. 6 , partially exploded ( Fig. 7a )

Fig. 8a, 8b

each a plan view or side view, partly in section, of stator rings,

Fig. 9a, 9b

each a plan view or side view, partly in section, of stator rings,

Fig. 10a, 10b

Side views of a drive shaft and a coupling with her agitator shaft and

Fig. 11a, 11b, 11c

depending on a plan view and side view of a rotor and a neck.

Fig. 1 shows a schematic overview of a mixing plant, which has a container F with built-in stirrer R and with a counter-driven bar stirrer W, which has an inlet pipe 19 at the lower end. This is a bottom flange 14 ( Fig. 5 ), with which a pipe socket 16 of a disperser 10 is attached to the housing 12 of a container F, for what Fig. 5 and 6 offer different examples. A feed line 30 with connection 32 opens with an inlet 38 (FIG. Fig. 3 The disperser 10 is connected by a return or recirculation line Z to the upper part of the container F, in the lid of which a lockable pressure system with spray heads is provided, which is provided for periodic cleaning. The disperser can alternatively also in the embodiment according to Fig. 5 be used without recirculation line.

Out Fig. 2 the typical procedure is evident. In a (omitted here) container F is kept according to the recipe, a carrier (reagent I) ready. A (also not shown) storage container provides an additive (reagent II); according to claim 10, this may be a hot wax. The feed tank is connected via a metering device to the inlet 30 to a premixing chamber 60 of the dispersing device 10.

In the container F, if present, the agitator R is started and then the disperser 10 is started. Reagent I now flows through the dispersing device 10 and via the recirculation line Z (or directly) back into the container F. The metering device on the receiver tank is turned on, so that reagent II as a partial flow R II enters the premixing chamber 60 of the disperser 10 and is in it the partial stream RI 'of reagent I in an extremely short time.

The components (RI + R II) are intimately dispersed in the premixing chamber 60, resulting in a fine to very fine distribution depending on the selected process conditions. The resulting partial flow R I + II combined and mixed due to the static pressure differences and the geometry of the premixing chamber 60 with the remaining main flow RI "of reagent I of the disperser 10. This product III, consisting of the Reagent II-enriched reagent I, is returned as the final stream E in the container F. It is often already the finished product. Its circulations via the dispersing device 10 are continued until the product III has the formulation concentration of reagent II in reagent I. In most cases, the addition of an emulsifier is not necessary or only in small doses. - Experiments have incidentally revealed that also other receptor-bound substances can be processed in a smaller amount.

Out 3 and 4 For details of the mixing zone and the pre-chamber 60, which will be described in connection with the following explanation of the basic structure with reference to the examples of Fig. 5 and 6 become clear.

A rotor shaft 24 passes through an inlet pipe 19. It has a recess 27 at the lower end, with which it is connected via a coupling projection 25 to the shaft 22 (FIG. Fig. 10a, 10b ) connected to a support flange 18 drive motor 20 is connected. Only dashed are in Fig. 5 and 6 the outlines of - at high power quite heavy - engine 20 indicated, as well (right) a side terminal box for (not shown) electrical connections. The motor shaft 22 has at the upper end as a second bearing a conical bearing 23 for stabilizing the rotor shaft 24, which is supported on disc springs 13 with a fixed bearing on the bottom flange 14 and a loose bearing on the support flange 18 which supports the pipe socket 16 and additionally by spacer bolts 28 on Bottom flange 14 is supported. The seal to the container by means of a mechanical seal 26th

The rotor shaft 24 carries the hub 51 of a rotor 50 and is rotatably connected at the free end above with a stirrer shaft 43 which holds a stirrer 44 in the form of a propeller. The underside of the rotor 50 is directly opposite the bottom flange 14. In this an inlet channel 38 - in particular obliquely - arranged, in which a feed line 30 opens, which is preferably integrated into the flange 14 extending parallel to the ground, for example in the radial direction. However, it can also be designed as an outer tube and be brought obliquely to the mouth of the inlet channel 38. For the hot wax supply from a (not shown) reservoir of the terminal 32 with a shut-off device 34 is present, for example, a rotary valve or a valve which is operable with a - optionally arranged differently - lever 36.

The bottom flange 14 is integrally or rigidly connected to a stator 40, which engages over the rotor 50 from above and has a suction port 45, below which there is a main space 15 which is bounded by the top or top surface 53 of the rotor 50 down. The stator 40 and the rotor 50 each have axially parallel sprockets, which are nested with minimal radial clearance. Thus, the stator 40 has an inner stator ring 41 with inner stator teeth 46 and an outer stator ring 42 with outer stator teeth 48. The rotor is provided with radially inner lobes 63 and outer lugs or teeth 65 therebetween Radial passages 66 are located ( Fig. 11a ). Corresponding radial passages 47 are provided on the inner stator ring 41 ( Fig. 8a ), as radial passages 49 on the outer stator ring 42 (FIG. Fig. 8b ). The lugs 63, 65 of the rotor 50 are perpendicular from its top 53 ( Fig. 11b ) and have inclined side and roof surfaces, wherein the upper end of the teeth 63 and 65 terminates in inclined surfaces 67. All teeth or lugs 63, 65 can have obliquely arranged wing surfaces 64 relative to the circumferential direction ( Fig. 11a, 11c ).

Important is the design of the rotor 50 (see above all Fig. 11b ). Its hub 51 has a central bore 52 and a flat end surface 54, to which a stepped stepped surface 55 can connect parallel to the top surface 53. At a radius which is determined by the position of the mouth of the inlet channel 38, the step surface 55 merges into a flat cone 56 from which a concave outer surface 58 branches off at a sharp tear-off edge 57, which approaches or approaches at a steeper angle at the peripheral edge 59 the top surface 53 expires. At this part, the rotor 50, which here has its largest diameter and at the periphery a number of preferably concavely curved or curved outlet channels 68, overlapped by the outer stator teeth 48 with minimum gap (see FIG. 3 and 4 ).

Between the inner boundary of the outer stator teeth 48, the outer surface 58 of the rotor 50 and the adjacent upper surface of the bottom flange 14, the premixing chamber 60 is arranged, which is for mixing and dispersing of central importance. In this small volume, to which in the respective circumferential position that of the respective outlet channel 68 belongs, coming from the feeder 30 hot reagent II is after deflection on the acting as a baffle flat cone 56 with the already existing in the main chamber 15 Medium I to a Mixture swirled. This passes as a partial flow R I + II through the associated outlet channel 68 to the outer stator teeth 48 and through the outer radial passages 49 therethrough in a deflection chamber 61 and flows in a dispersed manner on the housing 12 through the radial outlets 62 of the stator 40 in a (not shown) from container. The stirring member 44 continuously supplies the main stream RI from the container F to the inner main space 15 until the dispersion has reached the desired degree of homogenization. Via an outlet (not shown) of the final flow E of the finished product III can be deducted.

The embodiment of Fig. 6 is basically the same structure, which is why corresponding components are marked with already mentioned reference numbers. Here, the stator 40 is not formed as a hood, but as a cover plate, which is provided with the central suction port 45 and rigidly connected to a cylindrical housing 70, which also closes the bottom flange 14 fixed rigidly below. The preferably oblique inlet 38 is in turn connected to the terminal 32 by a trained as a ground-parallel radial channel in the flange 14 feeder 30 space-saving. At a peripheral location, the housing 70 has a nozzle 69 (FIG. Fig. 6 and 7b ) with a connection 72 for a (not shown here) return line to the top of the container F.

The stator plate 40 carries an attachment 17 which can be mounted thereon with a fastening flange 71 and surrounds the stirring element 44 in an inlet pipe 19 ( Fig. 7a ). The inlet pipe 19, which is welded to the flange 71, is rigidly connected to an upper flange 29, onto which an in - Fig. 7a shown separately - flange 39 can be placed, which can be screwed to the housing 12 and to a connected flange approach.

In a further design of the attachment 17, the housing 70 according to Fig. 7b a shortened wax supply port 32, which is welded as part of the bottom flange 14 directly below the housing 70 with this. In yet another example of Fig. 7c the terminal 32 is inserted directly into the wall of the housing 70, thereby achieving additional space savings.

A particular problem is that for the development of new formulations first work naturally in smaller laboratory equipment of eg 3 ... 16 I content with dispersers correspondingly low power (for example, 1.5 ... 5.5 kW). The implementation on an industrial scale makes conventional large and time-consuming effort, because the different thermal conditions and different Ratios of surfaces to volumes make the transition to large volumes of eg 500 ... 5000 I rather complicated, especially if a translation factor of 300 is exceeded. Many formulations are significantly influenced by the mixing of the hot wax additive with the relatively cold carrier substance. The process takes place here in Vordispergierraum whose volume depends mainly on the rotor diameter, which in turn determines the power consumption of the rotor in the 5th power. It turned out to be a great advantage of the adjusted partial flow method according to the invention that for the transition from a 3.0 kW laboratory machine to a 45 kW dispersing device a rotor enlargement is required only in the ratio 1: 1.72. This corresponds to a ratio of 1: 2.95 of the volume increase in the predispersion space, which is to be regarded as negligible compared to the translation factor 300. In practical experiments, the recipes developed in the laboratory facility could be transferred to the production plant in the same way, in full compliance of the product produced with the laboratory result. Due to the small 'active volume' and the elimination of a heating time of the carrier, the production time for this process step is shortened considerably, eg at 2000 kg for a batch cycle from the beginning of the container filling to the end of the pumping from an average of 2.5 h to 40 min , which in addition to a large increase in daily production also means a considerable energy saving.

Example of use A: Fatty acid-lime milk mixture

In the production of fatty acid-lime milk mixtures, e.g. for the recovery of cleaning agents, fatty acid is added as reagent II in the prechamber 60. The dissolved CaOH complex of the partial stream R I 'of reagent I (milk of lime) is sufficient to neutralize the weak fatty acid. During the subsequent mixing, the saturation concentration is reached again by the suspension of CaOH. The extremely disturbing formation of lime-fatty acid agglomerates is successfully avoided by the partial flow method.

Example of use B: Flocculant addition in water treatment

In water treatment and wastewater treatment, flocculants and coagulation inhibitors (eg aluminum sulfate) are added in the ppm range. Because one Homogeneous dosage of these agents in the plants is difficult, must be often overdosed, which means significant cost increase. It is possible to pass a partial stream of 10% to 1% of the water quantity via a dispersing device 10 with prechamber 60 and to supply the flocculant or anticoagulant to this quantity of water (via connection P4 of the disperser 10) in the partial flow method. The recirculation line Z leads directly back into the processing tank of the total amount of water. Thus, the addition takes place there in the much cheaper mixing ratio of 1:10 to 1: 100. The extremely short residence time of the flocculants in the shear area of the dispersing device prevents destruction of the molecular chains of the flocculants. A larger gap between rotor and stator can be an advantage.

Example C1: Exothermic processes

Many chemical reactions release heat. This heat must be dissipated to allow the reaction to proceed in a controlled manner. In the adjusted partial flow method according to the invention, the quantitative ratio of reagent I and reagent II can be set exactly to one another in such a way that the cooling of the recirculation line Z corresponds to the heat quantity of the heat of reaction.

Example C2: Endothermic processes

In endothermic processes, the heat input through the rotor / stator system 40/50 is often sufficient to obtain the required amount of heat for the solution. Here, a high energy density is advantageous, even if the particle / droplet size is secondary to the process itself.

Requirements for the dispersing device

1. a) eine Vormischkammer (60) von kleinem Volumen, in die ein Teilstrom R I' aus einem z.B. Reagenz I enthaltenden Behälter (F) gelangt;
2. b) eine Zugabemöglichkeit (32, 38) z.B. von Reagenz II in diese Vorkammer (60);
3. c) Einstellung einer gewünschten Druckverteilung durch den eingangsseitigen Umschlingungswinkel des Auslasses (69) bzw. durch das Querschnittsverhältnis der Austrittsöffnungen (bei Maschinen ohne Rezirkulationsleitung);
4. d) Einstellbarkeit des Volumens des Gemischstroms R I+II, beispielsweise durch Wahl geeignet geformter Mischwerkzeuge oder Vorgabe von Durchlaßvolumina der Statorzähne (46, 48);
5. e) Vorgabe der für die Produkthomogenität wesentlichen Teilstrom-Hauptstrom-Druckverhältnisse, z.B. durch trapezförmige Ausbildung der äußeren Statorzähne (48).

Two-stage dispersing forms the core of the process and apparatus of the invention. The main requirements for the dispersing device 10 are:

1. a) a pre-mixing chamber (60) of small volume into which a partial flow RI 'from a container containing eg reagent I (F) passes;
2. b) a possibility of addition (32, 38), for example, of reagent II into this antechamber (60);
3. c) setting of a desired pressure distribution by the inlet-side wrap angle of the outlet (69) or by the cross-sectional ratio of the outlet openings (in machines without recirculation line);
4. d) adjustability of the volume of the mixture flow R I + II, for example by selecting suitably shaped mixing tools or specification of passage volumes of the stator teeth (46, 48);
5. e) specification of the essential for the product homogeneity partial flow main flow pressure conditions, eg by trapezoidal formation of the outer stator teeth (48).

Thanks to suitable shaping of the premixing chamber 60 and high rotational speed of the rotor 50, a mixing and dispersing time in the millisecond range is possible. Thus, especially in process example A, a cooling of reagent II under the solidification limit is avoided even at high wax contents. By adjusting the mixing ratio, a favorable temperature level for homogenizing or dispersing is achieved.

The speed of the disperser motor should e.g. be adjustable by specifying frequency and / or constant output current. Thus, the introduced energy can be kept constant even when fluctuating during the process viscosity.

When emulsions or viscous products are made, it is convenient to return the recirculation outlet below the liquid level in the container to prevent air ingress.

For the method according to Example B, the unit should be provided with an external recirculation line (Z) which can be heated and / or cooled as required.

For working with a single machine (ie without cascade) a corresponding branching in the partial flow of the machine is necessary. If, for example, two dispersing devices are used, with a second, smaller dispersing device having a premixing chamber 60 for achieving the two-stage configuration, then, for the ultrafine dispersion, it can additionally be introduced into the return line Z from the second dispersing device Tank F a high pressure homogenizer to be switched. In the hot / cold process according to Example A, the end product, ie reagent III, is brought to the optimum temperature for the high-pressure homogenizer by the energy intake in the two dispersion stages and by the feed of the hot reagent II. This must be designed only for the partial flow R I + II, which saves costs and energy consumption and thus represents a significant advantage. This variant is particularly suitable for introducing "difficult products" such as vitamin E.

An intermediate switching of a high-pressure homogenizer is also possible with a two-stage single dispersing device 10, provided that only a suitable partial flow connection is present.

Recipe Examples a) Elegant night cream (recipe Henkel KGaA)

The ingredients of the hot phase - including beeswax - are melted in a container and brought to 80 ... 85 ° C. The amount is 2000 kg end product about 600 kg.

Ingredients of the cold phase are presented in the container F, is filled in from above water of about 15 ° C. Then vacuum is applied, for example 0.5 bar, and the other components of the cold phase are added while the homogenizer is running at medium speed for 5 minutes. The Wandgängige agitator R in the container F is also turned on after the addition of water. It is advantageous if the container F has a coaxial, counter-rotating stirring system, so that a more homogeneous remixing takes place.

The hot phase is then added via port 30, 32, which leads directly into premixing chamber 60. The disperser 10 rotates at about 3000 min ^-1. During the process, which lasts for about 15 minutes, the motor current must be kept constant at, for example, 40 A, which, although variable viscosities entail changes in the speed, but causes a constant energy input. The mixture is then stirred for 5 minutes with the disperser 10 switched off and with the disperser 10 switched on.

energy balance

25 min run of the 30 kW disperser incl. Discharge, power consumption 12.50 kWh Use 40 minutes slow speed of 5.5 kW mixer 3.67 kWh To heat the hot phase you need 35.00 kWh Total energy consumption 51.17 kWh.

In the conventional hot / hot process, which lasts at least 2.5 hours, the energy balance looks like this: Heating both product phases to 80 ... 85 ° C 116 kWh Dispersing operation for 0.5 h 15.5 kWh 2.5 h slow speed of the agitator 13 kWh Cool to 35 ° C at least 116 kWh total consumption 260.5 kWh.

It can be seen that the process sequence according to the invention in this example brings about an energy saving of around 210 kWh and, in addition, the production capacity more than triples due to the short production time.

b) hair dye

For the production of hair dyes, a hair color base is made, which is the same for all colors of the same type and determines the total amount of water required. Subsequently, the actual hair dye is prepared by incorporating the desired color-giving substances in a reduced amount of the hair dye base.

In a 3000 I system equipped with a dispersing device 10 and an opposing stirring system W, only as much water is added to produce the hair color base material in the hot / cold process according to claim 10 as in the conventional hair color process the lowest percentage of water is needed (generally the color is black).

Part of the color base is then placed in a smaller unit of e.g. Pumped around 250 I, which is equipped with a dispersing device 10 together with premixing chamber 60. Via the terminal P4, the color providing agent in the partial stream R II are added. The amount of water is chosen so that, taking into account the possibly lower, previously entered into the basic product amount of water in the final product III, the formulation ratio for the selected color is given.

The invention is not limited to the above-described embodiments, but can be modified in many ways. The hot / cold partial flow process can be used well in cases where reagent II is not rigid at room temperature but has a desirably low viscosity in the hot state, so that incorporation into reagent I is at a high energy level, such as are highly concentrated surfactants or vitamin E products. Thanks to the high concentration in the feed partial flow R II, the industry-standard cold / cold approaches can be run very economically. It is also possible, in the case of low to medium-viscosity substances, to reprogram a laboratory system designed for batch operation with a two-stage dispersing device 10 into a continuously operating production plant, for which only relatively inexpensive storage containers for the 'hot' and 'cold' starting materials and possibly a metering device are required.

It can be seen that a preferred procedure for homogenizing substances, eg pasty masses, and / or for producing emulsions with droplet sizes in the micron range a arranged on a container F disperser 10 with a bottom rotor / stator system 40, 50 and possibly used with conveying members 44. According to the invention, in a first stage, a hot precursor produced from a reagent or wax solution in the form of a secondary stream R II is dispersed with a metered partial stream of, for example, a cold carrier substance RI 'and in a second stage with a carrier main stream RI flowing in from above. The cool-down of the wax particles, which takes place in the 10 ms range, prevents their clumping, resulting in a stable mixture or emulsion with small droplet sizes which can be adjusted to suit the product by controlling the energy input at the rotor / stator system 40, 50. The rotor underside is associated with a premixing chamber 60 in which the secondary flow R II is entangled with the partial flow RI 'supplied from above / outside. The high-speed operation of the rotor 50 generates a reverse turbletab whose negative pressure for the self-metering of the secondary flow R II contributes. By first deflecting the wax-containing mixture R I + II from the prechamber 60 to the outside before accelerating it at the top of the stator and feeding it to the internal main flow RI ", its static pressure is exceeded Supply 30, 38 opens below the rotor 50, preferably near its outer region, into the pre-chamber 60, which is delimited by an outer stator ring 42 and via an outlet channel 68 into a main chamber 59 at the bottom of the rotor / stator system 40, 50th The outer stator teeth 48 extend as far as a bottom flange 14, which faces the rotor underside with a flat cone (56), a tear-off edge (57) and a steeper outer surface 58. An agitator 44 can be located directly above the center in the hood formed inlet 45 near the rotor 50 or in an inlet pipe 19 above the rotor / stator system 40, 50 sit, from which an outlet port 69 goes off permeable return line Z is at least partially installable outside the container F and / or tempered.

All of the claims, the description and the drawings resulting features and advantages, including design details, spatial arrangements and method steps may be essential to the invention both in itself and in various combinations.

LIST OF REFERENCE NUMBERS

A investment e effluent F container R agitator W straight-arm Z return 10 disperser 44 Stirrer / propeller 12 casing 45 suction 13 Disc springs 46 inner stator teeth 14 bottom flange 47 radial passages 15 main room 48 outer stator teeth 16 pipe socket 49 radial passages 17 essay 50 rotor 18 flange 51 hub 19 inlet pipe 52 central bore 20 drive motor 53 Top / top surface 21 motor flange 54 Hub end surface 22 motor shaft 55 step surface 23 cone-bearing 56 flat cone 24 rotor shaft 57 Transition / tear-off edge 25 coupling approach 58 outer surface 26 Mechanical seal 59 peripheral edge 27 recess 60 Before (mixed) chamber 28 Distance bolts 61 deflection 29 upper flange 62 Outlet openings ( Fig. 5 ) 30 Feeding (Leit) ung 63 inner approaches / teeth 32 Connection 64 wing area 34 shutoff 65 outer approaches / teeth 36 (Operating) lever 66 radial passages 38 Inlet (channel) 67 inclined surfaces 39 flange 68 outlet channel 40 Stator (dome / plate) 69 Support 41 inner stator ring 70 cylindrical housing 42 outer stator ring 71 mounting flange 43 agitator shaft 72 (Connection for) feedback

Claims (6)

1. Device for homogenising substances and/or producing emulsions having a droplet size in the µm range, comprising a disperser (10) arranged on a container (F), comprising at least one rotor/stator system (40, 50) close to the container base, the disperser (10) comprising a rotor (50), a stator (40) having a suction opening (45), an inflow of product from above and a base flange (14) comprising an inlet channel (38) having a supply line (30), and the stator (40) comprising an outer stator ring (42) having outer stator teeth (48) and radial passages (49), and an inner stator ring (41) having inner stator teeth (46) and radial passages (47), the stator (40) delimiting a deflection chamber (61) outside the outer stator ring (42), the inner and outer stator teeth (46, 48) being oriented axially downwards from above, and the rotor (50) having sprockets which are oriented axially upwards, characterised in that the rotor (50) has a underside which is opposite the base flange (14), the outer stator teeth (48) overlapping the rotor (50) with a minimal distance at a peripheral edge (59) in a contact-free manner, projecting up to the base flange (14), and corresponding with a downwardly oriented tooth edge of the rotor (50) such that periodically aligning channels are formed between the deflection chamber (61) and a pre-mixing chamber (60) when the rotor (50) is rotated, the rotor (50), the stator (40) and the base flange (14) of the disperser (10) delimiting the pre-mixing chamber (60) between the underside of the rotor (50), the outer stator ring (42) of the stator (40) and the base flange (14) of the disperser (10), the rotor underside having a flat cone (56) extending up to the region of the pre-mixing chamber (60) and having at least one conical or concave outer surface (58) having a relatively steep cone angle or central angle, the distance between the underside of the rotor (50) and the base flange (14) being configured to increase radially from the inside to the outside, and the inlet channel (38) underneath the rotor (50) leading into the pre-mixing chamber (60).
2. Device according to claim 1, characterised in that a main space (15) is formed underneath the suction opening (45) of the stator (40), which space is delimited towards the bottom by an upper side (53) of the rotor (50).
3. Device according to either claim 1 or claim 2, characterised in that the rotor (50) has an upper side (53), a stepped surface (55) which is arranged parallel to the upper side (53), and a peripheral edge (59), the rotor (50) having its largest diameter at the peripheral edge (59).
4. Device according to claim 3, characterised in that the rotor (50) has an end face (54), a flat cone (56) and a tear-off edge (57), which form the underside of the rotor (50) together with the stepped surface (55) and the outer surface (58), the end face (54) being attached to the stepped surface (55), the stepped surface (55) transitioning into the flat cone (56) and the concave outer surface (58) being detached from the flat cone (56) at the tear-off edge (57).
5. Device according to any of claims 1 to 4, characterised in that the rotor (50) has a number of concavely curved or arched outlet channels (68) on the periphery.
6. Use of a device according to any of claims 1 to 5 to homogenise substances and/or produce emulsions having a droplet size in the µm range.

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