EP1121974A1 - Mixing method and apparatus - Google Patents

Abstract

According to a novel partial flow method, different reagents (I, II) can be quickly and intimately mixed with a dispersing device (10) which, for example, has a rotor / stator system (40, 50) on the bottom of a container (B), in particular for emulsion production. A e.g. Wax-containing preliminary product can be hot dispersed in a premixing chamber (60) by feeding (30, 38) below the rotor (50) with a metered partial stream (R I ') of a cold carrier substance. The resulting mixture is then mixed with a main stream (R I ') flowing in from above. In contrast to known dispersion 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 terms of time and place by introducing them into the premixing chamber (60). The underlying idea is that an optimal emulsion can only be created if a homogeneous phase mixture is present. In known dispersing devices, part of the highest shear range is used for mixing. <IMAGE>

Description

The invention relates to a method and an apparatus for mixing flowable substances, in particular by dispersing and emulsifying, according to the Preamble of claim 1 or claim 9 and claim 16.

Process engineering is generally used to produce desired end products from a recipe-based ratio. For example, for mixing pasty masses and emulsions, especially with droplet sizes in the µm range, However, it can be advantageous if two or more reagents are used in the agitator Process in other proportions can be brought together to the creation of the desired product in terms of mixing time, total amount and optimize temperature. Especially when a large amount of a first Reagent is to be combined with a smaller amount of a second reagent, thermodynamic and flow processes can lead to a different procedure make it useful or even necessary.

With regard to the reasons for different quantity approaches, DE 20 04 143 A1 states that at the production of suspensions or emulsions with small particle sizes short dwell time is required to prevent so-called Oswald ripening, i.e. the Large particles grow at the expense of smaller ones as a result of redissolving With crystal growth If you add a phase, supersaturation is achieved which Bacterial count per unit volume; after nucleation begins, the Addition of additional solutions mainly for the growth of the already formed germs or crystals, which reduces the total number of microunits created. This results in the technical specification in the cited publication and similarly in US 2,641,453 Teaching derived to merge two phases over a coaxial pipe section. However, a temperature adjustment inevitably occurs. On such heat exchange before mixing can be extremely high for some processes be undesirable.

The object of the present invention is to provide an agitator in an economical manner to achieve optimal mixing of such reagents, at least initially have to be at different temperatures, or at all have different temperature behavior. This will be a further development known mixing methods in connection with dispersants aimed, in particular have a coaxial toothed rotor / stator arrangement. Operational Permanently reliable means of production should be as simple as possible in the construction, Can be manufactured and assembled with minimal effort and can be used conveniently and trouble-free be, without sacrificing product quality. With regard to environmental protection how to save costs, energy consumption must be minimized, both in Batch operation as well as generally in a continuous process.

Main features of the invention are set out in claims 1, 9 and 16. Refinements are the subject of claims 2 to 8, 10 to 15 and 17 to 29.

According to claim 1, the invention relates to a two-stage dispersion process in which one from a main stream of a reagent I coming from a container Branches off and this a second partial stream (side stream) of a mixture with a reagent II, which is generated in a premixing chamber, whereupon the mixture of the two partial streams by a rotatingly driven disperser in the rest of the main stream. This process is extremely economical and highly effective. Small partial flows can be easily and with very little Adjust the inertia as required, easiest using a dosing pump. The Partial flow technology also has the advantage that the concentration of the Addition reagent must only have the quantitative ratio related to the partial flow. This also applies to the otherwise often difficult phase emulsion emulsification in the Hot / cold process.

With extremely fast throughput, even distribution can be achieved problematic products by mixing in accordance with claim 2 intensified by pulsation in a ring or outlet channel, preferably with a cyclical one Pressure build-up and release in the antechamber. In particular also by dosing the Partial flows and possibly by changing the speed of the disperser to control the volume and pressure conditions. This is how reagents can be used process well at different temperatures and in different concentrations. You can do this with known dispersers with a coaxially nested Use rotor / stator system in which shear forces between tight adjacent concentric baskets, at least one of which is driven in rotation will homogenize passing mix that is periodically aligned channels are removed; depending on their geometry and dimension Different speed components and turbulence at the shear gap on. However, a cascade arrangement of two dispersing devices is also suitable with different working volumes, provided the throughput in the premixing chamber of the second disperser is controllable.

According to claim 3, cyclical pressure differences support such a disperser the rapid and even distribution of the reagents by phasing high pressure each reagent I is conveyed into the premixing chamber, which in each subsequent phases of lower pressure with the reagent II with swirling in the antechamber dispersed evenly under pulsation. The mixing therefore goes procedurally optimal in front of you, regardless of those to be set for the end product Quantitative ratios. Thanks to the extremely short residence time, it takes place in the premixing chamber from e.g. only 5 ms only a minimal heat exchange takes place, so that a hot reagent II cools very little while it reagent I is mixed thoroughly.

An important feature of the invention according to claim 4 is that main stream and partial flows receive different energy densities, resulting in optimal dispersion and emulsion formation with the smallest possible particle or droplet sizes contributes significantly. Specifically, the mixture of the partial streams in the premixing chamber an energy density that is significantly - e.g. by at least one Magnitude - is higher than the energy density in the main stream. Unless one of them works differently without introducing high specific energies, for example to bring about a desired chemical reaction, you can still achieve a strong one Equalization that supports this process. For example, subtleties easily achieve below 0.5 µm. For non-Newtonian liquids takes place due to the energy increase when flowing into the premixing chamber in the Generally there is a reduction in viscosity, which the mixing with low-viscosity substances significantly improved.

It is advantageous if, according to claim 5, the energy density and residence time in the partial flow, i.e. the volume and time-related energy input is changeable, in particular by setting such that one leading to an emulsion envelope critical energy density is not achieved, for example for the production of Mayonnaise, dressing sauces, etc. is very important.

If a separate dispersing device is used, this becomes continuous according to claim 6 charged only with that part of the main stream of R I that in the Premix the reagent R II in the amount corresponding to the total flow is metered supplied, whereby one in the outlet stream of the dispersing device R II over concentration reached, whereupon the over concentrated mixture (R I + II) in a small-sized high-pressure homogenizer processed and with the remaining Reagent R I 'is mixed. Compared to the state of the art the effort required is significantly reduced. Nevertheless, high quality end products are achieved in an extremely efficient way.

According to claim 7 in a - preferably given by the premixing chamber - Mixing range the mixture (R I + II) in terms of temperature and ratio adjusted, without being exposed to significant shear stress, what an area of maximum shear given by the rotor / stator system connects, especially on the long tooth edge of the rotor. The adjusted partial flow process This design goes far beyond conventional technology. It can be further developed according to claim 8 that a from the reagents Mixed phases due to different speeds and different static Pressures are generated in the premixing chamber, with a phase I directly in the latter is promoted and a phase II by pulsation due to cyclical pressure differences reaches the premixing chamber via inlet channels.

For homogenizing substances, e.g. pasty masses, and / or to produce Emulsions with droplet sizes in the µm range, using an in or on a container arranged disperser with at least one rotor / stator system, especially near the bottom of the container, and if necessary with conveyors for a carrier substance stream, the invention looks for the independent Claim 9 a two-stage generation and mixing of defined partial flows, in a first process step from a reagent or wax solution Intermediate product generated and this in a second process step to the carrier substance stream will be added. The term wax is part of the present Invention for all substances that are solid at room temperature and at elevated temperature are liquid or flowable, e.g. also fats, paraffins, esters and the like. A big advantage The new procedure is that the carrier is not Wax melting temperature must be brought, but keep room temperature can. The resulting product still has a very high degree of homogeneity because can control the droplet size by adjusting the energy density according to the product; it therefore fulfills all quality requirements.

According to claim 10, a hot reagent stream (side stream) in the first process step with a dosed branch from the main stream of the cold carrier substance Partial stream combined and - while introducing the necessary for the droplet size Energy - dispersed, whereupon the mixture to produce the final product in the second Process step mixed with the remaining part of the carrier main stream becomes. The optimization of the volume ratio of the carrier substance partial flow to Pre-product partial flow significantly reduces the number of product cycles; already after The desired concentration of reagent II in reagent I can be circulated be reached. For example, a processing time of only 15 minutes for 2,000 kg Cream easily obtainable. Agglomerate formation as in Oswald ripening does not occur here because the amount of emulsion required to absorb the wax addition is low and a noticeable cooling is thus avoided. The wax can be incorporated into the carrier substance at high energy density without streaking become. The particle fineness is determined by the energy input supported in the rotor / stator system, in which the increase in surface energy applied or exceeded many times over. With the then taking place shock-like cooling on the large volume of the main stream of cold Carrier substance hardens the wax particles, causing secondary agglomerate formation prevented. This results in a homogeneous particle size distribution and thus a significantly improved product behavior.

The measure of claim 11, according to which the method is self-metering, is very advantageous is designed by the hot supplied below the rotor / stator arrangement Partial reagent stream (side stream) in a premixing chamber with a first one Partial stream of the carrier substance dispersed and the resulting precursor over a Recycle diluted with the main stream flowing in from above and into one Final stream is mixed. It is advantageous if in accordance with claim 12 In the premixing chamber an inverted drum is created, the negative pressure of which is Dosage of the partial reagent stream or side stream contributes. When the In the rotor / stator system, rotors can reach peripheral speeds above 20 m / s occur so that the medium present in the premixing chamber thanks to strong centrifugal acceleration is pressed vigorously through the disperser to the outside and experience an increase in energy.

The mixing of partial and main stream can according to claim 13 by control of the static pressures are supported, in particular in the second partial flow static pressure is generated that exceeds that of the main flow. That leaves achieve surprisingly well that the premixing chamber the lower and assigned radially outer parts of the rotor and the preliminary product from there initially is diverted to the outside before being accelerated at the top of the stator and the main stream flowing radially further inside. Poses the pressure in the main room one expediently by dimensioning and choosing the ratio of the inlet / outlet cross sections on.

In contrast to the known dispersion systems, where mixing and Shear are carried out simultaneously in the area of the greatest shear gradient, the present process separates mixing and shear in terms of time and location. Thanks to the introduction into the premixing chamber, an optimal emulsion can be created be by presenting a homogeneous phase mixture. In contrast in known dispersing devices, a considerable part of the highest range Shear used for mixing. The one that has passed through the rotor / stator system Product can be used as an exit stream according to claim 14 in another Convey containers in which the product is kept homogeneous, e.g. by means of a slow-speed agitator. This saves energy and continues the Oswald ripening opposite.

In the event that powder components are required for the end product, see claim 15 before that they can be admixed to the main stream from above, so that they with great Speed recorded in the material flow and swirled quickly.

The invention further relates to a device for homogenizing Fabrics, e.g. B. pasty masses, and / or to produce emulsions with droplet sizes in the µm range and with a disperser on or in a container has at least one rotor-stator system near the bottom of the container, with one Product inflow at the top and optionally with at least one in it arranged in the upper area, especially for carrying out the method according to one of the preceding claims. This ends in accordance with claim 16 a feed for particularly hot reagent into a premixing chamber below the rotor, which have an outlet duct with a main space at the bottom of the Rotor / stator arrangement is fluidly connected.

Thanks to such a predispersion chamber, which requires very little space, it is the one according to the invention Device energetically extremely advantageous. It represents an essential one Further development of facilities, for example according to DE 296 08 712 U1, the Stator and / or rotor lugs with - seen in cross section or development - trapezoidal shape or have a trapezoidal shape, i.e. wedge structures that define the flow influence significantly due to different areas and tear-off edges. Also compared to a dispersing device according to DE 296 08 713 U1, which is adjusted of the axial distance between stator and rotor disproportionate changes in the Bringing shear gap volume, the invention achieves with the installation of a premixing chamber a considerable acceleration of the dispersion.

According to claim 17, the premixing chamber is in the outer region of the rotor its underside and the limiting housing side arranged or formed, specifically such that it extends from the center of the underside of the rotor to a premixing chamber outlet enough. With minimal space requirement, this prechamber is on top of this Optimally housed on the rotor / stator system. The outer Stator ring according to claim 18 stator teeth projecting downward from the main space have, which overlap the rotor circumference with a minimum distance and the bottom flange, which is centrally opposite the bottom of the rotor pass. This formation causes the generation of an increased static pressure in the premixing chamber or at least contributes to it. The latter thereby becomes a limited small volume, in which an intensive predispersion - for example of supplied Hot reagent - without annoying cooling.

Advantageously, according to claim 19, a feed line opens into a e.g. oblique Inlet duct, which is integrated into the bottom flange as a parallel radial duct, namely opposite the outer rotor underside. You can see the construction like this form that the rotor at its top maximum diameter or circumference. has and from a peripheral edge or rounding from an outer surface to the bottom of the rotor jumps in while the top of the rotor is flat or concave.

A very intensive radial delivery of the medium is achieved if in line with Claim 20 on the rotor underside a deflecting body from one to the area of Antechamber-reaching flat cone with at least one cone-shaped or concave Outer surface is formed with a steeper cone or center angle, the transition between adjacent deflection surfaces preferably designed as a sharp tear-off edge is to create an additional swirl. So at least two conical and / or curved surfaces adjoining each other at an obtuse angle form a step surface enclose the rotor hub peripherally and angles that become steeper towards the outside to have. These deflection surfaces guide the partial flow particularly effectively into the main room about. The powerful centrifugal flow on the outer stator ring therefore already has one Axially parallel component, which makes the partial flow entry into the main room highly effective supported.

According to claim 21, a preferred design has a stator with a hood, which delimits a deflection chamber outside the outer stator ring, which is close the bottom flange is provided with outlet openings distributed over the circumference, the conveying member being formed directly above the center of the hood Inlet sits near the rotor. This extremely compact arrangement is directly on one The bottom of the container can be flanged and is ensured by recirculation in a narrow High degree of homogenization.

Dispersers are typically manufactured with very tight tolerances and assembled precisely. Considering the small minimum distances in the axially adjustable rotor / Stator system, which can be up to 0.1 mm, is according to claim 22 as a hollow shaft motor trained drive extremely useful, that on the bottom flange and is mounted on a rectangular support flange. So that in the hollow shaft The non-positively inserted drive shaft remains dimensionally stable during operation Rotor shaft preferred through stops and disc springs within a mechanical seal axially supported so that an elongation of the hollow shaft and thus the Drive shaft is only possible in the direction away from the base flange. This will be on Surprisingly simple way reliably compensates for heat effects from the engine underneath. Although the temperatures of the drive shaft in As a result, continuous operation, for example, can reach up to 120 ° C dispersers located above practically no thermal expansion takes place; much more inevitable linear expansion of the hollow motor shaft occurs when heated in the direction away from the disperser. So thanks Consistently narrow gaps on the rotor / stator system permanently optimal shear effect.

According to claim 23, the pressure distribution is in order to set a pulsation effect Disperser controllable on the outlet side, preferably by choosing the flow path and the flow path or the wrap angle in the outlet channel behind the Outlet connection or by the area dimensioning and the arrangement of the outlet openings, so that an adaptation to special operating conditions on relatively simple Way can be made.

In line with claim 24, an attachment which can be flanged onto the container bottom has a the feed pipe enclosing the conveying element, which makes the medium particularly powerful is sucked in. A line leads from an outlet connection, which e.g. via a valve is switchable and returns 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 element is braked. One avoids air pockets if the line is below of the minimum product level present in the container is returned.

The return line can at least partially outside of the Container, which in a laboratory version e.g. 16 l and industrial e.g. Hold 10,000 I. can be installed and tempered as required. With high dispersion rates, around 30 to 50 kW, is the new possibility of external cooling of great advantage.

A further reduction in droplet sizes is achieved according to claim 26 by that one or both stages of the disperser can be subjected to ultrasound are for which the rotor forms an intermittent reflector. The one next to the stator teeth rotating rotor teeth cause an intermittent-continuous Uniformity in the product.

The development of claim 27 is significant, according to which the passage volume in Area of the premixing chamber or its volume itself adjustable or changeable is, especially by changing the rotor shape and / or the stator shape with unchanged Shear edge length. If you change the stator openings in the second stage (at otherwise the same device), the shear gradient and thus the volume-related Energy is affected while the shear edge delimits the premixing chamber Stator teeth remain the same. In order to influence the partial current energy density and the length of stay can, conversely, according to claim 28, the shear edge length with unchanged Premixing chamber volume can be adjusted or changed. With relatively simple equipment Means can be an optimal adaptation of the procedure to the achieve the respective mixing task.

As an alternative to the aforementioned integrated designs, the device can be designed according to Claim 29 be designed as a separately attachable predispersion stage, especially for economical Retrofitting existing homogenizing or dispersing systems. Such separate dispersing device is continuously only with that part R I "of Main stream charged, the reagent R II in the in the premixing chamber Total current R I is metered in an appropriate amount, whereby one Excess concentration of R II in the outlet stream of the dispersing device has been reached. The An over-concentrated mixture can be created by a considerably smaller high-pressure homogenizer processed and then with the remaining reagent stream R I ' to be mixed.

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 emerge from the wording of the claims and from the following description of exemplary embodiments with reference to the drawings. In it show:

Fig. 1

1 shows a schematic process container in an axial sectional view with a flanged-on dispersing device,

Fig. 2

a flow diagram,

Fig. 3

2 shows a partial sectional view of a rotor / stator arrangement with a premixing chamber,

Fig. 4

3 shows an enlarged section corresponding to area IV in FIG. 3,

Fig. 5

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

Fig. 6

2 shows an axial sectional view of a similar homogenizer with an attachment,

7a, 7b, 7c

6, partially in an exploded view (FIG. 7a),

8a, 8b

a top view and a side view, partly in section, of stator rings,

9a, 9b

a top view and a side view, partly in section, of stator rings,

10a, 10b

Side views of a drive shaft and a stirrer shaft that can be coupled with it

11a, 11b, 11c

a top view and a side view of a rotor and an approach.

Fig. 1 shows a schematic overview of a mixing plant that a container F with built-in agitator R and with a bar stirrer that can be driven in opposite directions W has an inlet pipe 19 at the lower end. This stands on a floor flange 14 (FIG. 5) opposite, with which a pipe socket 16 of a disperser 10 on Housing 12 of a container F is attached, for which FIGS. 5 and 6 different Offer examples. A feed line 30 with connection 32 opens out with an inlet 38 (Fig. 3) on the bottom flange 14. The disperser 10 is by a return or Recirculation line Z connected to the upper part of the container F, in the Cover a lockable printing system with spray heads that protrudes for periodic Cleaning is provided. Alternatively, the disperser can also be designed 5 can be used without a recirculation line.

The typical process sequence can be seen from FIG. In a (omitted here) Container F holds a carrier substance (reagent I) according to the recipe ready. A storage container (also not shown) provides an addition means (Reagent II); according to claim 10, this can be a hot wax. The display case is via a metering device with the inlet 30 to a premixing chamber 60 connected to the dispersing device 10.

In container F - if present - the agitator R is started and then the Disperser 10 started. Now reagent I flows through the dispersing device 10 and via the recirculation line Z (or directly) back into the container F. Die Dosing device on the storage container is switched on, so that reagent II as Partial stream R II enters the premixing chamber 60 of the disperser 10 and settles therein mixed with the partial flow R I 'of reagent I in an extremely short time.

The components (R I + R II) are intimately dispersed in the premixing chamber 60, depending on the process conditions selected, a fine to very fine distribution results. The resulting partial flow R I + II combines and mixes due to the static pressure differences and the geometry of the premixing chamber 60 with the rest Main stream R I "of reagent I of the dispersing device 10. This product III, consisting of reagent I enriched with reagent II, the final stream E in returned the container F. It is often the finished product. Its round about the dispersing device 10 are continued until the product III Recipe concentration of Reagent II in Reagent I has. Mostly adding one Emulsifier not necessary or only necessary in small doses. - By the way, have attempts show that other formulation-bound substances are also processed in smaller quantities can be.

3 and 4 show details of the mixing area and the pre-chamber 60, which in connection with the following explanation of the basic structure based on the Examples of FIGS. 5 and 6 will become clear.

A rotor shaft 24 passes through an inlet pipe 19. It has a recess at the lower end 27, with which it is connected to the shaft 22 (FIG. 10a, 10b) a drive motor 20 fastened to a support flange 18 is connected. Just 5 and 6 are dashed lines in outline of the - which is quite heavy at high power - Motor 20 indicated, also (right) a side terminal box for (not shown) electrical connections. The motor shaft 22 is second at the upper end Bearing a cone bearing 23 for stabilizing the rotor shaft 24, which is via disc springs 13 with a fixed bearing on the bottom flange 14 and with a loose bearing on Support flange 18 which supports the pipe socket 16 and additionally by spacers 28 is supported on the bottom flange 14. The container is sealed by means of a mechanical seal 26.

The rotor shaft 24 carries the hub 51 of a rotor 50 and is at the free end above it with a stirring shaft 43 rotatably connected, the stirring element 44 in the form of a Propellers. The bottom of the rotor 50 is the bottom flange 14 directly across from. In this an inlet channel 38 - in particular at an angle - is arranged in the a feed line 30 opens, which preferably in the flange 14 parallel to the floor is integrated, for example in the radial direction. However, it can also formed as an outer tube and obliquely to the mouth of the inlet channel 38 be introduced. For the hot wax supply from a storage container (not shown) there is the connection 32 with a shut-off device 34, e.g. a rotary valve or a valve that is equipped with a - optionally also arranged differently - Lever 36 is operated.

The bottom flange 14 is integrally or rigidly connected to a stator 40, which overlaps the rotor 50 from above and has a suction opening 45, below which there is a main space 15 is located, which is from the top or top surface 53 of the rotor 50 is capped. The stator 40 and the rotor 50 each have axially parallel Sprockets that are nested with the least radial play. So he owns Stator 40 an inner stator ring 41 with inner stator teeth 46 and an outer Stator ring 42 with outer stator teeth 48. The rotor is located radially further inside inner lugs or teeth 63 and with outer lugs or teeth 65 provided, between which there are radial passages 66 (Fig. 11a). Appropriate Radial passages 47 are present on the inner stator ring 41 (FIG. 8a) as well Radial passages 49 on the outer stator ring 42 (Fig. 8b). The approaches 63, 65 of the Rotors 50 protrude vertically from its upper side 53 (FIG. 11b) and have inclined ones Side and roof surfaces, with the upper end of teeth 63 and 65 in inclined surfaces 67 expires. All teeth or lugs 63, 65 can be to the circumferential direction have inclined wing surfaces 64 (Fig. 11a, 11c).

The design of the rotor 50 is important (see above all Fig. 11b). His hub has 51 a central bore 52 and a flat end face 54, to which a stepped step surface 55 can connect parallel to the top surface 53. On a radius through the Position of the mouth of the inlet channel 38 is predetermined, the step surface 55 goes in a flat cone 56, of which a concave on a sharp tear-off edge 57 Outer surface 58 comes off, which at a steeper angle on the peripheral edge 59 near or on the top surface 53 runs out. At this part the rotor 50, which is its largest here Diameter and on the circumference a number, preferably concavely curved or has curved outlet channels 68, from the outer stator teeth 48 with a minimum gap overlapped (see FIGS. 3 and 4).

Between the inner boundary of the outer stator teeth 48, the outer surface 58 of the Rotor 50 and the adjacent top of the bottom flange 14 is the premixing chamber 60 arranged, which for the mixing and dispersing of central Meaning is. In this small volume, to that in the respective circumferential position that of the outlet channel 68 in question, this becomes from the feeder 30 Coming hot reagent II after deflection on the flat cone, which acts as a baffle 56 with the medium I already present in the main room 15 to form a mixture swirled. This passes as partial flow R I + II through the assigned outlet channel 68 to the outer stator teeth 48 and through the outer radial passages 49 into a deflection chamber 61 and flows dispersed along the housing 12 through the Radial outlets 62 of the stator 40 into a container (not shown). The agitator 44 leads the main flow R I from the container F continuously to the inside Main room 15 until the dispersion reaches the desired degree of homogenization Has. The end stream E of the finished product can be passed through an outlet (not shown) III be deducted.

The embodiment of FIG. 6 is basically constructed in the same way, which is why corresponding Components are identified with the reference numbers already mentioned. Here is the stator 40 is not designed as a hood, but as a cover plate, which is aligned with the central one Provided suction opening 45 and rigidly connected to a cylindrical housing 70 is that also rigidly attached bottom flange 14 closes below. The preferably inclined inlet 38 is in turn with the connection 32 through a parallel to the floor Radial channel in the flange 14 formed feed 30 connected to save space. At a circumferential point, the housing 70 has a connection piece 69 (FIGS. 6 and 7b) 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 is attached to it with a fastening flange 71 is mountable and surrounds the stirring element 44 in an inlet pipe 19 (FIG. 7a). That with the inlet pipe 19 welded to the flange 71 is rigid with an upper flange 29 connected, onto which a flange ring 39 - shown separately in FIG. 7a - can be placed is the one on the housing 12 or on a flange attachment connected to it can screw.

In a further construction of the attachment 17, the housing 70 according to FIG. 7b a shortened wax feed port 32, which is part of the bottom flange 14 is welded to the housing 70 directly below it. Im still another 7c is the connection 32 directly into the wall of the housing 70 used, thereby achieving an additional space saving.

A particular problem is that for the development of new recipes first, of course, in smaller laboratory facilities e.g. 3 ... 16 I content with dispersers correspondingly low power (for example 1.5 ... 5.5 kW) is worked. The Implementation on an industrial scale makes conventionally large and time consuming Trouble because of the different thermal conditions and different Ratios of surfaces to volumes transition to large volumes of e.g. Design 500 ... 5000 I quite complicated, especially if a translation factor of 300 is exceeded. Many recipes are made by mixing the hot Wax additive with the comparatively cold carrier substance significantly influenced. The process takes place here in the predispersion room, the volume of which is mainly depends on the rotor diameter, which in turn is the 5th power consumption of the rotor. It turned out to be a great advantage of the adjusted partial flow process according to the invention that for the transition from a 3.0 kW laboratory machine on a 45 kW dispersion device, a rotor enlargement only in the ratio 1: 1.72 is required. This corresponds to a ratio of 1: 2.95 to the volume increase in the Predispersion space, which compared to the translation factor 300 as vanishing is negligible. In practical trials, the ones worked out in the laboratory system Recipes are identical to the production plant, and in full agreement of the product produced with the laboratory result. Because of the small, active volume and the elimination of a heating-up time Carrier substance significantly shortens the production time for this process step, e.g. at 2000 kg for a batch cycle from the beginning of the container filling to the End of pumping from an average of 2.5 h to 40 min, which in addition to a large one Increasing daily production also means significant energy savings.

Example of use A: fatty acid-lime milk mixture

In the production of fatty acid-lime milk mixtures, e.g. for the extraction of Detergents, fatty acid as reagent II is metered into the pre-chamber 60. The in Solution of the CaOH complex of the partial stream R I 'from reagent I (milk of lime) sufficient to neutralize the weak fatty acid. When mixing is carried out the CaOH in suspension again reaches the saturation concentration. The Extremely disruptive formation of lime-fatty acid agglomerates is caused by the partial flow process successfully avoided.

Example of use B: Flocculant addition in water treatment

In water treatment and wastewater treatment, flocculants and Coagulation inhibitors (e.g. aluminum sulfate) added in the ppm range. Because one Homogeneous dosing of these agents in the plant is difficult, often be overdosed, which means considerable cost increases. You can see a partial flow from 10% to 1% of the amount of water via a dispersing device 10 with a prechamber 60 and this amount of water (via connection P4 of the disperser 10) Add the flocculant or anticoagulant using the partial flow method. The recirculation line Z leads directly back into the processing basin of the total water volume. So the addition takes place there in the considerably more favorable mixing ratio from 1:10 to 1: 100. The extremely short residence time of the flocculants in the shear area the dispersing device prevents destruction of the molecular chains of the Flocculant. A larger gap between the rotor and stator can be advantageous.

Example of use C1: Exothermic processes

Heat is released in many chemical reactions. This heat must be dissipated to allow the reaction to proceed in a controlled manner. With the adjusted partial flow method according to the invention, the quantitative ratio of reagent I and Reagent II can be set exactly to each other and so that the cooling of the recirculation line Z corresponds to the heat quantity of the heat of reaction.

Example of use C2: Endothermic processes

In the case of endothermic processes, the heat input from the is often sufficient Rotor / stator system 40/50 to get the required amount of heat for the solution. Here a high energy density is advantageous, even if the particle / droplet size is of secondary importance in terms of procedure.

Requirements for the dispersing device

a) eine Vormischkammer (60) von kleinem Volumen, in die ein Teilstrom R I' aus einem z.B. Reagenz I enthaltenden Behälter (F) gelangt;

b) eine Zugabemöglichkeit (32, 38) z.B. von Reagenz II in diese Vorkammer (60);

c) Einstellung einer gewünschten Druckverteilung durch den eingangsseitigen Umschlingungswinkel des Auslasses (69) bzw. durch das Querschnittsverhältnis der Austrittsöffnungen (bei Maschinen ohne Rezirkulationsleitung);

d) Einstellbarkeit des Volumens des Gemischstroms R I+II, beispielsweise durch Wahl geeignet geformter Mischwerkzeuge oder Vorgabe von Durchlaßvolumina der Statorzähne (46, 48);

e) Vorgabe der für die Produkthomogenität wesentlichen Teilstrom-Hauptstrom-Druckverhältnisse, z.B. durch trapezförmige Ausbildung der äußeren Statorzähne (48).

The two-stage dispersion forms the core of the method and device according to the invention. The main requirements for the dispersing device 10 are:

a) a premixing chamber (60) of small volume, into which a partial flow RI 'from a container (F) containing, for example, reagent I, passes;

b) an addition option (32, 38), for example of reagent II, into this antechamber (60);

c) setting a desired pressure distribution by the wrap angle of the outlet (69) on the inlet side or by the cross-sectional ratio of the outlet openings (in the case of machines without a recirculation line);

d) adjustability of the volume of the mixture flow R I + II, for example by selecting suitably shaped mixing tools or specifying the passage volumes of the stator teeth (46, 48);

e) Specification of the partial flow-main flow pressure ratios essential for product homogeneity, for example by trapezoidal design of the outer stator teeth (48).

Thanks to suitable shaping of the premixing chamber 60 and high speed of the rotor 50 a mixing and dispersing time in the millisecond range is possible. So you avoid especially in process example A, even with high wax contents, cooling of reagent II below the solidification limit. By adjusting the mixing ratio becomes a favorable temperature level for homogenizing or dispersing reached.

The speed of the disperser motor should e.g. by specifying frequency and / or constant output current. So the energy brought in simply kept constant even when the viscosity fluctuates during the process become.

When emulsions or viscous products are made, the spout is run the recirculation expediently below the liquid level in the container in order to To prevent air entry.

For methods according to example B, the unit should have an external recirculation line (Z), which can be heated and / or cooled as required.

For working with a single machine (i.e. without cascade connection) is one appropriate branching in the partial flow of the machine is necessary. Used e.g. two dispersers, with a second, smaller disperser for Achieving the two-stage has a premixing chamber 60, it can be used for ultrafine dispersion additionally in the return line Z from the second disperser to Container F a high pressure homogenizer can be switched. In the hot / cold process according to example A, the end product, i.e. Reagent III, by absorbing energy in the two dispersion stages and by supplying the hot reagent II to that for the High pressure homogenizer brought optimal temperature. This only has to be for the partial flow R I + II can be designed, which saves costs and energy consumption and thus represents a significant advantage. This variant is particularly suitable for Introduction of "difficult products" such as Vitamin E.

Interposing a high-pressure homogenizer is also a two-stage individual dispersing device 10 possible, provided only a suitable partial flow connection is available.

Recipe examples a) Elegant night cream (Henkel KGaA formula)

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

Ingredients of the cold phase are placed in the container F, in the water from above of approx. 15 ° C. Then vacuum is applied, for example 0.5 bar, and the other components of the cold phase are added during the homogenizer Runs at medium speed for 5 minutes. The wall-mounted agitator R in tank F is also switched on after adding water. Here it is cheap 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 the connection 30, 32, which leads directly into the premixing chamber 60. The disperser 10 runs at about 3000 min ^-1 . During the process, which lasts about 15 minutes, the motor current must be kept constant at, for example, 40 A, which, with variable viscosities, does cause changes in speed, but causes constant energy input. The mixture is then stirred for a further 5 minutes, with the disperser 10 switched off and with the switch on 10.

Energy balance

25 min run of the 30 kW disperser including discharge, power consumption 12.50 kWh Consume 40 min slow speed of the 5.5 kW agitator 3.67 kWh To heat the hot phase you need 35.00 kWh Total energy consumption 51.17 kWh.

With the conventional hot / hot process, which lasts at least 2.5 hours, the energy balance is as follows: Heating of both product phases to 80 ... 85 ° C 116 kWh Dispersing operation for 0.5 h 15.5 kWh 2.5 h slow running 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 is a in this example Energy savings of around 210 kWh and additionally due to the short Production time more than tripled production capacity.

b) hair dye

For the production of hair dyes, a hair dye base is made, which is for all colors of the same type are the same and determine the total amount of water required. Then you make the actual hair dye by incorporating the desired coloring substances in a reduced amount of the hair color base forth.

In a 3000-liter system equipped with a dispersing device 10 and an opposing one Stirring system W is equipped to produce the hair color base in Hot / cold method according to claim 10 only as much water added as in conventional process for hair color with the lowest percentage of water is required (generally the color is black).

Part of the color base material is then transferred to a smaller plant, e.g. 250 I. pumped around, equipped with a dispersing device 10 including premixing chamber 60 is. Via the connection P4, the agents supplying the color are transferred to the Partial stream R II added. The amount of water is chosen so that under Consideration of the possibly smaller, entered in advance in the basic product Amount of water in the final product III is the recipe-based ratio for the selected one Hue is given.

The invention is not limited to the above-described embodiments, but rather can be modified in many ways. The hot / cold partial flow process can work well in Cases are used where Reagent II is not rigid at room temperature, but has a desirably low viscosity when hot, so that incorporation in reagent I at a high energy level, for example when it comes to highly concentrated surfactants or vitamin E products. Thanks to the high concentration Industry-standard cold / cold approaches can also be used in the feed stream R II be driven very economically. It is also possible with low to medium viscosity Fabrics a laboratory system designed for batch operation with two stages To convert the dispersing device 10 into a continuously operating production system, which is why you only need relatively inexpensive storage containers for the 'hot' and 'cold' raw materials as well as a dosing device may be required.

It can be seen that a preferred procedure for homogenizing Fabrics, e.g. pasty masses, and / or for the production of emulsions with droplet sizes a disperser 10 arranged on a container F in the μm range with a ground-level rotor / stator system 40, 50 and possibly with conveying elements 44 used. According to the invention, a reagent or Wax solution produced, e.g. hot intermediate product in the form of a side stream R II a metered partial flow e.g. cold carrier R I 'dispersed and in a second stage with a main stream R I "flowing in from above. The cooling of the wax particles taking place in the 10 ms range, i.e. in a shock-like manner prevents them from clumping together. A stable mixture or emulsion is created with low, by controlling the energy input to the rotor / stator system 40, 50 droplet sizes adjustable according to the product. The rotor bottom is a premixing chamber 60 assigned, in which the secondary flow R II with that from above / outside supplied partial stream R I 'is swirled. The high speed of the rotor 50 produces one inverted trombone, the negative pressure for self-dosing of the secondary flow R II contributes. By first the wax-containing mixture R I + II from the pre-chamber 60 is diverted to the outside before being accelerated at the top of the stator and supplies the internal main flow R I ", its static pressure is exceeded. Man can mix powder components from above. A partial flow feed 30, 38 opens below the rotor 50, preferably near its outer area, into the pre-chamber 60, which is delimited by an outer stator ring 42 and via an outlet channel 68 in a main room 59 on the underside of the rotor / stator system 40, 50 leads. The outer stator teeth 48 protrude up to a bottom flange 14, the bottom of the rotor with a flat cone (56), a tear-off edge (57) and a steeper outer surface (58) faces. A stirrer 44 can be located directly above the centric in the hood formed inlet 45 near the rotor 50 or in an inlet pipe 19th sit above the rotor / stator system 40, 50, of which an outlet connection 69 goes off. A lockable return line Z is at least partially outside of the container F can be installed and / or tempered.

All arising from the claims, the description and the drawing Features and benefits, including design details, spatial arrangements and process steps can be used both individually and in a wide variety of ways Combinations be essential to the invention.

Reference list

A

investment

E

Outlet flow

F

container

R

Agitator

W

Bar stirrer

Z.

return

10th

Disperser

12th

casing

13

Belleville washers

14

Bottom flange

15

Main room

16

Pipe socket

17th

Essay

18th

Supporting flange

19th

Inlet pipe

20th

Drive motor

21

Motor flange

22

Motor shaft

23

Cone bearing

24th

Rotor shaft

25th

Coupling attachment

26

Mechanical seal

27

Recess

28

Spacer

29

upper flange

30th

Supply

32

Connection

34

Shut-off device

36

(Operating) lever

38

Inlet (duct)

39

Flange ring

40

Stator (hood / plate)

41

inner stator ring

42

outer stator ring

43

Agitator shaft

44

Agitator / propeller

45

Suction opening

46

inner stator teeth

47

Radial diffusers

48

outer stator teeth

49

Radial diffusers

50

rotor

51

hub

52

Central bore

53

Top / top surface

54

Hub face

55

Step surface

56

Flat cone

57

Transition / tear-off edge

58

Outside surface

59

Peripheral edge

60

In front of (mixing) chamber

61

Deflection chamber

62

Outlet openings (Fig. 5)

63

inner approaches / teeth

64

Wing area

65

outer lugs / teeth

66

Radial diffusers

67

Bevels

68

Exhaust duct

69

Support

70

cylindrical housing

71

Mounting flange

72

(Connection for) return

Claims (29)

Two-stage dispersion process, in which one from a container (F) coming main stream (R I) of a reagent I branches off a partial stream (R I ') and this a second partial stream (side stream R II) of a mixture with a Reagent II supplies that in a premixing chamber (60) of a rotor / stator system (40, 50) is generated, whereupon the mixture of the two substreams (R I + II) by a rotatingly driven disperser (10) in the rest Main current (R I ") promotes. A method according to claim 1, characterized in that the mixing is intensified by pulsation in an annular or outlet channel, preferably with cyclical pressure build-up and reduction in the premixing chamber (60). Process according to Claim 2, characterized in that reagent I is conveyed into the premixing chamber (60) in phases of high pressure and in that the mixture is dispersed uniformly in phases of low pressure with swirling with reagent II. Method according to one of claims 1 to 3, characterized in that the main stream (RI) and the sub-streams (R I ', RI ", R II) receive different energy densities, preferably the mixture of the sub-streams (R I + II) in the An energy density is impressed on the premixing chamber (60) which is considerably higher than the energy density in the main flow (RI), for example by at least one order of magnitude. Method according to one of claims 1 to 4, characterized in that the energy density and residence time in the or each partial stream (R I ', RI ", R II) can be changed, in particular by setting such that one leading to an emulsion change critical energy density is not reached. Method according to one of claims 1 to 5, characterized in that when a separate dispersing device is used, this is fed continuously only with that part (RI ") of the main stream (RI) which contains the reagent R II in the premixing chamber (60) Total current (RI) is metered in the appropriate amount, thereby achieving an over-concentration of R II in the outlet stream of the dispersing device (10), whereupon the over-concentrated mixture (R I + II) is processed in a small-sized high-pressure homogenizer and mixed with the remaining reagent RI 'is mixed. Method according to one of claims 1 to 6, characterized in that in a mixing area (premixing chamber 60) the mixture (R I + II) is adjusted with regard to temperature and quantity ratio without being exposed to any significant shear stress, and that the rotor is exposed to it / Stator system (40/50) given the area of maximum shear, especially on the long tooth edge of the rotor (50). Method according to claim 7, characterized in that a phase mixture is generated from the reagents (RI, R II) by different speeds and different static pressures in the premixing chamber (60), a phase I being conveyed directly into the latter and a phase II through Pulsation due to cyclical pressure differences reaches the premixing chamber (60) via inlet channels. Method for homogenizing substances, e.g. pasty masses, and / or for producing emulsions with droplet sizes in the µm range, using a disperser (10) arranged in or on a container (F) with at least one rotor / stator system (40 , 50), in particular near the bottom of the container, and optionally with conveying elements (R; 44) for a carrier substance stream (RI), characterized by a two-stage design of the process with the generation of defined partial streams (R I ', RI ", R II) such that in in a first process step, a preliminary product (R I + II) is produced from a reagent or wax solution and this is added to the carrier substance stream (RI ") in a second process step. Process according to Claim 9, characterized in that a hot reagent stream (secondary stream R II) is combined and dispersed in a premixing chamber (60) in the first process step with a partial stream (R I ') branched off from the main stream (RI) of the cold carrier substance, whereupon the mixture (R I + II) to produce the end product (R III) is mixed in the second process step with the remaining part (RI ") of the carrier main stream. Method according to Claim 10, characterized in that it is designed to be self-metering in that the partial reagent stream (secondary stream R II) fed below the rotor / stator system (40, 50) in the premixing chamber (60) with a partial stream (R I ' ) dispersed the carrier substance and the resulting preliminary product (R I + II) via a return line (Z) diluted with the main stream (RI) flowing in from above and mixed to a final stream (E). A method according to claim 10 or 11, characterized in that the reverse rotation of the rotor (50) in the premixing chamber (60) produces a negative pressure, the negative pressure of which contributes to the metering of the partial reagent flow (secondary flow R II). Method according to one of claims 1 to 12, characterized in that the mixing of the partial streams (R I ', R II) with the main stream (RI ") is supported by controlling the static pressures, in particular by adding a static one in the secondary stream (R II) Pressure is generated that exceeds that of the main stream (R I '). Method according to one of claims 1 to 13, characterized in that the outlet stream (E) is conveyed from the disperser (10) into another container in which the product is kept homogeneous, for example by a slow-running agitator (W). Method according to one of claims 1 to 11, characterized in that powder components are added to the main stream (RI) from above. Device for homogenizing substances, e.g. B. pasty masses, and / or for the production of emulsions with droplet sizes in the µm range, with a on or in a container (F) arranged disperser (10), with at least one rotor / stator system (40, 50) close to Container bottom, with a product inflow (45) from above and optionally with at least one conveying member (44) arranged in this upper region, especially for carrying out the method according to one of the preceding claims, characterized in that a feed (30) below the rotor (50) , 38) opens into a premixing chamber (60) for a particularly hot reagent (II) and that the premixing chamber (60) via an outlet channel (68) with a main space (59) on the underside of the rotor-stator system (40, 50 ) is fluidly connected or - connectable. Apparatus according to claim 16, characterized in that the premixing chamber (60) is arranged or formed in the outer region of the rotor (50) between its underside and an outer stator ring (42), specifically in such a way that it is separated from the rotor hub (51, 54 ) extends to a premixing chamber outlet channel (68). Apparatus according to claim 17, characterized in that the outer stator ring (42) has stator teeth (48) projecting downward from the main space (49), which overlap the rotor circumference in a contact-free manner and which extend as far as one of the underside of the rotor (54 up to 57) center-facing bottom flange (14) are sufficient. Device according to one of claims 16 to 18, characterized in that a feed line (30) opens into an inlet channel (38) which is integrated in the bottom flange (14) as a radial channel parallel to the bottom, particularly with respect to the outer underside of the rotor (55, 56) . Device according to one of claims 16 to 19, characterized in that on the rotor underside a deflecting body from a flat cone (56) reaching to the region of the prechamber (60) with at least one conical or concave outer surface (58) with a steeper cone or A central angle is formed, the transition between adjacent deflection surfaces (56, 58) preferably being designed as a sharp tear-off edge (57). Device according to one of claims 16 to 20, characterized in that it has a stator (40) with a hood which delimits a deflection chamber (61) outside the outer stator ring (42), which is close to the bottom flange (14) and extends over the circumference Distributed outlet openings (62) is provided, and that the conveyor member (44) sits directly above the inlet (45) formed centrally in the hood near the rotor (50). Device according to one of claims 16 to 21, characterized in that it has a drive designed as a hollow shaft motor (20) which is mounted on the base flange (14) and on a support flange (18) at right angles thereto, and in that the rotor shaft ( 43) is supported, for example by stops and disc springs (13), that a length extension of the hollow shaft (43) and thus the drive shaft (22) is only possible in the direction away from the base flange (14). Device according to one of claims 16 to 22, characterized in that the pressure distribution can be controlled on the outlet side in order to set a pulsation effect in the disperser (10), in particular by selecting the flow path and the flow path or the wrap angle in an outlet channel behind the outlet nozzle (68) or by dimensioning the area and arranging the outlet openings (62). Device according to one of claims 16 to 23, characterized in that an attachment (17) which can be flanged onto the container bottom (14) has an inlet pipe (19) surrounding the conveying member (44) above the rotor / stator system (40, 50) and that from this an outlet pipe (68) with a shut-off line (Z) goes off, which - preferably below the product level - leads back into the container (F). Device according to claim 24, characterized in that the return line (Z) can be installed and / or tempered at least in sections outside the container (F). Device according to one of claims 16 to 25, characterized in that one or both stages of the disperser can be subjected to ultrasound, for which the rotor (50) forms an intermittent reflector. Device according to one of claims 16 to 26, characterized in that the passage volume in the region of the premixing chamber (60) or its volume itself can be adjusted or changed, in particular by changing the rotor shape and / or the stator shape with unchanged shear edge length. Device according to one of claims 16 to 27, characterized in that, for the purpose of influencing the partial flow energy density and the dwell time, the shear edge length is set or changed with the premixing chamber volume unchanged. is changeable. Device according to one of claims 16 to 28, characterized in that it can be designed or designed as a separately attachable predispersion stage.

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