FI125546B - Arrangement and method for mixing the liquid - Google Patents

Description

An arrangement for mixing a liquid and a method

Background

The invention relates to an arrangement for mixing a liquid, which arrangement comprises at least one sekoitinparin with sekoitinparissa a first and a second mixer, which Agitators are arranged vertically, parallel to each other and in opposite directions of rotation on which the first and second stirrer comprises at least one agitator arranged in the mixing-men that mixer elements which are arranged sekoitinaltaaseen, which is free of baffles, i. The mixer is attached to the wall of the vertical plates, which sekoitinallas has a circular or rectangular shape and that the Agitators are arranged at a distance from the center of said circular or rectangular sekoitinaltaassa a distance from the center line.

The invention further relates to a method for mixing a fluid, comprising: a liquid mixed adapted sekoitustilavuuteen, mixed in a mixing volume of at least one sekoitinparilla sekoitinaltaassa, which is free of baffles, i. The mixer wall attached to the vertical plates, which sekoitinparin Agitators are arranged vertically and rotate parallel to each other but in opposite directions, the Stir-tustilavuus comprises a shaped circular or rectangular-shaped mixer, and the Agitators are arranged from the center at a distance from said circular, or rectangular-shaped sekoitinaltaassa a distance from the center line .

Known for a number of liquid handling processes in which the liquid is mixed, either on its own or in another containing any dangerous phase. The second phase material may comprise a solid, liquid and / or gas. Such fluid handling processes can be, for example, water treatment processes such as aeration, hydrometallurgical processes such as dissolution, Net, precipitation, crystallization, oxidation, reduction, absorption, training, or flotation liquid-liquid extraction processes, and to certain ion exchange processes, .

In the above mixing processes can be a problem to achieve a uniform blend of performance - especially in the mixing unit is a great space-vuuksinen. A further problem is the large volume of mixing equipment, the mixer drive motors and gears, large size and high price. Another problem may be a blend of low power, ie. Implementation of the required agitation to consume very much energy.

Short description

Now, the present invention is to provide a new type of arrangement and a method for mixing a liquid.

The arrangement and method according to the invention is characterized by what is stated in the independent claims characterizing parts. Other embodiments of the invention are characterized by what is disclosed in the other claims.

According to the idea of ​​the arrangement comprises at least one mixed insofar-tinparin with sekoitinparissa a first and a second mixer whose mixed insofar-tinakselit are arranged parallel to each other and in opposite directions of rotation on which the first and second stirrer comprises at least one matched mixed insofar-tinakseliin of the mixing, and the mixer elements is tinaltaaseen-mixed insofar arranged, which is free of baffles.

According to one method, the idea of ​​mixed fluid is adapted sekoitustilavuuteen, mixed in a mixing volume of at least one of the pair-mixer, arranged sekoitinparin Agitators for rotation parallel to each other but in opposite directions, and mixed-liquid mixed insofar tinaltaassa, which is free of baffles.

Inventive embodiments are also presented in the description part and drawings of the present application. The inventive content of the application can also be defined differently than in the claims presented below. The inventive content may also consist of several separate inventions, especially if the invention is considered in the light of explicit or implicit subtasks or in respect of advantages or sets of advantages achieved. In this case, to be of some of the attributes contained in the claims below may be separate inventive concepts. Various features of the embodiments of the present invention can within the framework of the basic inventive concept in conjunction with other embodiments.

The arrangement and method allow mixed-phase liquid solution, either as such or at least one other containing any dangerous phase, wherein the other agent phase may comprise a solid solution and / or gas.

Thus, the arrangements, the method may be for example a part of the water treatment process or the hydrometallurgical process, such as dissolution, Net, precipitation, crystallization, oxidation, reduction, absorption, training, flotation, ion exchange or liquid-liquid extraction process.

According to one idea, the arrangement and method of operation is performing a number of rotation of the mixers, which are arranged in vertical direction and grouped sekoituspareiksi sekoitinaltaaseen, for example, a closed-mixed insofar tinreaktoriin. Sekoitinallas may take the form of a cylinder, for example. Sekoitinparien grouping and the number may be freely chosen as necessary for each specific process. Each of the mixers is sekoitinparissa direction of rotation opposite to each other. In this way even large volumes, for mixing patterns to manage and sekoitinparien sub-flows and the vortices can be cumulatively to strengthen and regroup unused vir-absorbing baffles. Reactively braking baffles are not required at all, in which case the mixer produces shaft power can be developed by primary current in full exercise of mixed-signal and the impeller-swirling.

Said baffles are mounted on a vertical wall of the mixer in practice, the boards are an integral part of the mixing reactor types known in the art, it koitusaltaita. Baffles prevent the cells from the fluid consisting of a stirred otherwise, which arises when the mixer the circumferential direction of the rotating liquid rises to the mixer wall. Baffles received a substantial part of the agitator shaft power produced by the reactor to improve the mixtures-efficiency. High torque on flow-related harm must take into account used in technical solutions. These will raise the cost of sekoitusrat-solutions not only in the basic investment, but also in the form of increased maintenance and repair costs.

According to one idea, the arrangement and the method is achieved by mere agitators active mix, which refers to the use of a mixture of reactive flow problems. The required mix of dynamics, therefore, be achieved without the use of static flow side structures. The stirrer caused by the partial flows of liquid to act as a dynamic flow of the disadvantage caused by the mixer at least one other part-flows - and of course vice versa. As a result, the total shaft power can be used in the blend decreased as the mixers primäärisekoitusvyöhykkeet can cover a much larger proportion of the total volume to be mixed as is normal for rotating the agitating member and disadvantages based on the flow of the solution.

According to one idea, the mixture can be even more efficient by increasing the volume-specific mixing power shaft, since the arrangement reduces the size of the indi vidual mixers and also the drive end of the motor and possible gearbox.

There's this idea that efficient mixing is utilized by increasing the volumes, for the size and / or the introduction of new types of mixing reactors and reservoirs. For example, the volume of lieriömuotoisen the reactor can be increased by more than 300 m3, up more than 500 m3. Such large lieriömuotoiset reactors are not meaningful in the prior art sekoitusratkai-Suissa sharply tilting the engines, gearboxes and sekoitinrakentei-for the sake of. Especially related to the necessary flow of harm solutions, for example, their troublesome Attaching the reactor structures, will be technically difficult to implement. For example the reactor kumiointi a coating of rubber or the like. Elastic material, the manufacturing steps complicate the baffles quite substantially. In addition, the coupling head is very heavy.

According to one idea, the arrangement comprises one or more sekoitinparin arranged in a pool of water such as a lake, pond, river or other similar natural water bath. Such a solution can be used, inter alia, aerating or chemical water dispensing. One or more sekoitinpari can also be adapted to built a pool of water such as lagoons or water purification plant vedenkäsittelyaltaa-tion.

It has been found that the arrangement and the method can be a mixture of cells and / or mixing the combined effect of the pairs of the mixer thanks to the use of even large volumes, for aerating. According to an idea of ​​the aeration are used for the agitator-type mixing element at the same time sekoitinak-open lakes, so that the upper mixing element is of greater axial or lower than the lower agitators. This can be applied, for instance 30 ° - 65 ° blade angles. This type of solution provides aeration, a lower power requirement than prior art ilmastussekoittimissa, which are typically radial mixers. Such a ilmastusratkaisu based on the momentary and local pintavortekseihin through which air is drawn by the strong downward flow. There's this idea that climate-tusilmiötä can be enhanced by running mixers with individual between 5-30% of special rotational speeds at the same time as the supreme impeller surface distance is reduced over the 0.4 - 1.0 times the impeller diameter. In cases requiring further aeration can be enhanced by using the abbreviation gls lower mixer (gas, liquid, solid) in sekoitinelin- known, as is disclosed in US 4,548,765, for example, an overhead stirrer and paddle wide paddle stirrer, a blade angle of 30 °, for example.

According to one method, a concept, a stirred mixture of liquid in a pattern that extends over the whole of the mixer of the effective use of the volume of a liquid volume. A balanced mix of pattern is implemented against each other sekoitinparien rotating stirrers. This method makes it possible to achieve perfect or nearly perfect blend of figurative and virtaussymmetria. As a result, the lateral forces on sekoitinaltaaseen and support structures can be successfully minimized.

Sekoitinpareja may be, for example one, two, three, four, five etc. Sekoitinparien combinations to form such sekoitinkohtaisia ​​circulation currents which guide and intensify each other mixers the intermediate areas, causing on the outside sekoitinpariryhmityksen directed suction is pushing strokes and thereby extending over the whole liquid holding one or useampiosaista circulation flow.

Sekoitinkohtaiset affect the rotational speeds of the individual mixers circulating currents and their speed differences between these directions. According to the idea of ​​a second mixer sekoitinparin rotational speed is greater than or less and flows outwardly due to sekoitinparin directed away from or closer to this second mixer. In this case, the fluid volume is formed extending over the whole circulation of the mixing space or more less subject to rotation-flow, depending on whether the blend of all the pairs of mixers similar in speed or not.

In proximity to a wall of the mixer in accordance with the idea of ​​sekoitinparien mixers adapted to be rotated in the same direction, making it possible to enhance the total liquid volume of complete circulation flow.

Further, the form may be more extensive mixing patterns, for example, four pieces of two sekoitinparin a four-forming sekoitinalueita the mixer can be grouped in a similar manner as the mixing of two pairs of mixers are grouped. In this way a complete sixteen sekoitinkonstellaatio a grouping of the mixer. Similarly, we can from the three sekoitinparin perusryhmityksestä end up with a more comprehensive kol-menkymmenenkuuden mixer sekoitinkonstellaatioon.

Further, the above can be grouped sekoitinkonstellaatiota even larger second-order constellations, ending at the next sixty four and two hundred sixteen I sekoittimi- combination. Such constellations can be used, for example, natural waters such as ponds oxidation.

It should be noted, however, that even with one sekoitinparilla can be very cost-effectively increase the effective size of the reactor up to 300 m 3, two pairs of up to 1000 m 3, a pair of three up to 2000 m3 up to eight and a pair of up to 20 000 m3.

According to one idea of ​​the area, where a single mixer element rotates, is 0.5 - 1.5% in volume more than 1000 m3 near the mixing of the total area, while the lower portion of the agitating surface is not more than 10% mixing in a volume of less than 100 m3. Thus, the entire impeller and, in particular related sekoitinmoottoreiden and gearboxes, and the mass can be kept at a reasonable level.

The stirrer of the mixing type can be selected freely in the case of a special unit of the process according to the requirements. There's this idea that the mixing means used to paddle stirrer. The mixing means can be adjusted, if necessary, a number of different levels in the same agitator.

A single impeller shaft can be arranged, for example two or three mixing element, which may be of the same or which may differ from each other. According to one idea, the impeller shaft is provided with three paddle stirrer, of which the top blade angle is relatively small, for example 20 ° - 30 °, to the horizontal plane, the central blade angle is equal to or slightly larger, for example 30 ° - 40 °, and the bottom of the mixing blade angle remains the same or even slightly larger, for example 40 ° - 60 °. This gives mixtures of Ho weighted at the bottom of the mixer, thus contributing to the pulverous solid suspendointumista example, the gas dispersion and / or chemical reactions.

According to one idea of ​​the mixer elements are arranged and dimensioned so that they are relative to other mixers the mixing elements lomittumattomia. The term lomittumaton means that sekoitinelinten trajectories do not intersect with each other during the mixing. Mixer elements are side by side and rotating in opposite directions. Sekoitinparin mixer elements moving closest parallel. This can be achieved by more than käyttötilavuu-ing reaching a uniform mixture of the entire effective.

In such cases, the blend that do not require intense vortices promote the formation of a reaction, for example, dissolving or some oxidation reactions may be used, for example hydrofoil-like purely axial blade. These can also manage large sekoitustilavuuk-dips that could rise to between 1000 m3 - up to 20,000 m3.

A first mixer Sekoitinparin mixer elements may be of the type, dimensions and placement impeller shaft similar to the second mixer same sekoitinparin. Alternatively, sekoitinparin it-mixers mixer elements differ in type, dimensions and / or impeller shaft placement.

There's this idea that the mixing means used for publication helix type of body described in Fl 19,901,691. The inventors have found that this is particularly suitable for use in accordance with sekoitinaltaissa virtaushaitattomissa due to the need to buy a flat shaft power of the mixer, particularly the axial direction and the choice of the mixing height / diameter ratio of each particular case.

Helix of the mixing height / diameter ratio increases, can be switched to a modified helix type, which is characterized in that the mixer vertical direction of the division into several, for example two - six different parts. There's this idea that it is therefore sufficient that the mixer elements cover 20-80%, preferably 30-70% mix of volume on high, because of high blending mode-volume of the helix mixers cumulative lifting or suppressing effect is so great that continuous sekoitinulottuvuus Close to close the mixing volume of the base of the volume of the surface is unnecessary. It is noted, however, that the mixer elements can of course be dimensioned above the height of the shorter or longer.

According to the idea of ​​the mixing helix comprises a bent pipe coil that can be produced directly rise of the right-angle al hioputkea a controlled bending. A suitable increase in the angle may be between 8 ° - 50 ° depending on the intended use.

-Increasing direction or a heavy impact on the helix of the mixing shaft can be increased by flattening the coil-forming tube in connection with the bending. Litistämisaste tube may be between 0 - 50% of the initial pipe in diameter. Litistämissuunta may for example be convergent direction of the spinner, but it may deviate from that direction, for example, 0 - 35 ° and from this direction, so that the helix of the mixing blend of heavy lifting or partially extends outwardly therefrom.

The pipe wall can also be opened to the trailing side. This can be added to the turbulence caused by seinäsekoitinelimen. If there is a tube of circular and mixing the direction of lifting, open area can extend over half the tube cross-section when viewed in the direction reverse the tube, for example, at the interval of 02 and 08, or one of the cover a smaller area, such as at 03 and 07 range. In this review the direction at 12 means the pipe cross-section of the upper face and at 6 am, respectively, the lowest point. Also, flattened tubes can be opened in a similar manner.

One idea is that the process is managed throughout the effective mixing volume optimally. This situation can be achieved, for example, so that the first mixer is fitted in the cylindrical sekoitinparin mixed insofar tusaltaassa-cylinder farther away from the center of the second mixer. When two or more sekoitinparia can do the same, or may be adapted to some sekoitinpareista mixing tank farther from the center than others.

According to one idea, the sekoitinaltaassa used almost mixer-systems rate of the diameter of the control element, for example a cylindrical outer surface. The ratio of the diameter of the steering element to the diameter of the mixers can be in the range 0.4 - 1.0. Control of the element cross-section may be circular, oval, or polygonal, such as three, four five or six corners. The control panel may comprise a flow control profiling. According to one idea is that the control element extends through the entire mixing tank and forms a support structure of the mixers, which among other things carries the mixers drawing heads. The control element may be adapted, for example, cylindrical sekoitinaltaassa the center of the pool. The center arranged it could increase the circulation flow in the mixer, such as mixer also sekoitinparien flows towards the city center and next sekoitinparin the transition phase this out.

The control element surface can be adapted for controlling the flow of at least one flow control. In this way the distinctive kiertovirtauk can contribute to the formation of over-the size of the effective mixing volume.

There's this idea that improving the mixing performance characteristics by adding a mixture of the volume of turbulence. This can be done aa, for example, by selecting the mixing of the first pair of mixing the direction of raise and another heavy. Such a solution can be particularly useful when the mixed liquid is thick and thus heavy movements of sludge. The solution is obtained slurry surface zone of greater involvement of the mixing event. At the same time the bottom zone of the mixing equalized, because it is absorbed more efficiently by mixing and stirring the primary mixing zone. The situation is like this, mainly with regard to blade mixers and mainly concerns the axial mixers, partly helix mixers.

Lastly, the use of several of the mixer instead of one massive mixer is advantageous to lower investment and operating costs. This is a particularly important advantage when the required mixing an engine power of 300 kW - 500 kW or greater. Having more than one mixer in addition to improving the efficiency of mixing and reliability. Additional operating security, in particular the fact that one or even more of the mixer can be temporarily disabled without the mixing process must be completely stopped. In most of the mixing process is sufficient to maintain the stirring mixer one. This is a very significant advantage, particularly when the mixing process is part of a multi stage treatment process.

According to one mode or the elongate tube, through which the mixed fluid flows in accordance with the idea of ​​the mixer is arranged. Sekoitinparin mixers are therefore in their own sekoitinputkissaan. This idea of ​​a particular embodiment of the arrangement comprising two sekoitinparia, which mixers are close to each other in a square array, each in their own, matched up sekoitinputkessaan. Each of the mixing direction is axially heavy sekoitinkohtaisten rotation for directing flows straight down. Sekoitinkohtaiset circulation flows are combined to each other below the combined downflow tubes, which can be fed an additive such as a chemical, air and / or oxygen. The additive is carried down with the flow of the blending mode to the bottom zone.

Arrangement One idea is that it comprises at least one sekoitinparin with sekoitinparissa a first and a second mixer, which it-koitinakselit are arranged parallel to each other and in opposite directions of rotation on which the first and second stirrer comprises at least one of it-koitinakseliin arranged in the mixing means that the mixing member is dimensioned and arranged so that the relation of the second mixer mixing elements lomittumaton sekoitinparin.

An idea of ​​the method is that the mixed fluid is adapted sekoitustilavuuteen, mixed in a mixing volume of at least one-mixed insofar tinparilla, arranged sekoitinparin Agitators for rotation parallel to each other but in opposite directions, and the liquid is stirred, mixed insofar keeper means, which are mutually lomittumattomia.

BRIEF DESCRIPTION OF THE DRAWINGS

Some embodiments of the invention will be described in more detail in the accompanying drawings, in which Figure 1a shows a schematic view of a general construction of the arrangement from the side and partly in cross section, Figure 1b shows schematically the arrangement shown 1a is a top view in partial cross-section, Figure 1c shows schematically the arrangement shown 1a per-spektiivikuvantona and partly in cross section, Figure 2a shows schematically the general structure of another embodiment of the arrangement from the side and partly in cross section, Figure 2b shows schematically the arrangement shown in 2a, a top view and partly in cross-section, Figure 2c shows schematically the arrangement shown in 2a per-spektiivikuvantona and partly in cross-section, Figure 3 schematically shows a third arrangement general the structure of the side and partly in cross section, Figure 4 shows a schematic view of a fourth arrangement and a method top view and partly in cross-section, Figure 5 shows a schematic view of a fifth arrangement and method top view and partly in cross section, Figure 6 schematically shows a sixth arrangement and method top view and partly in cross-section, Figure 7a schematically shows a seventh an arrangement and method for a top view in partial cross-section, Figure 7b shows the schematic organization and method 7a of Figure another embodiment of a top view in partial cross-section, Figure 8 shows a schematic view of an eighth arrangement and method top view and partly in cross section, Figure 9 shows a schematic view of a ninth arrangement and a method top view and partly in cross-section, Figure 10 schematically shows the structure of one of the mixing cross section, and Figure 11 shows a schematic view of a second agitating member structure in cross section, Figure 12a shows a schematic view of a tenth general construction of the arrangement from the side and partly in cross-section, Figure 12b shows schematically the arrangement shown in 12a of the top , Figure 13 shows schematically the general structure of an eleventh arrangement from the side and partly in cross-section, Figure 14 schematically shows the general structure of the twelfth arrangement from the side and partly in cross section, and Figures 15a - 15c show schematically a flowing liquid-ordinated arrangements top.

Figures embodiment of the invention is shown in a simplified manner. Similar parts are marked with the same reference numerals.

Detailed description

Figure 1a shows schematically the structure of a general arrangement side view in partial cross section, Figure 1b a top view in partial section and perspective view in Figure 1c and partly in cross-section.

The arrangement 1 comprises two sekoitinparia 2, which each have a first mixer and a second mixer 3a, 3b.

Each mixer 3a, 3b comprises a spinner axis 4. Stir-tinakselit 4 are arranged parallel to each other and in opposite directions to pivot. The first mixers 3a rotates in the clockwise and the other counter-clockwise mixers 3b seen from above.

Each mixer 3a, 3b comprises at least one fitted to the shaft 4 and the rotating with the mixing means 5.

Mixer elements 5 are arranged and dimensioned such size that they are relative to other mixers the mixing elements lomittumattomia. The term lomittumaton means that sekoitinelinten 5 trajectories do not intersect with each other during the mixing.

Mixer elements 5 are, paddle mixer, which is adapted to the mixer two pieces each. Agitator preferably comprises 2-8 wings of a blade. First mixers 3a of blade mixers, paddle angles relative to the horizontal plane of the mixers are opposite to each other with respect to the angles of the shoulder 3b. In other words, if the second mixer 3b blade angle of a °, a first mixer 3a-men blade angle (180 - a) degrees. Since the first mixers 3a is arranged to rotate in the opposite direction to the other mixers in the direction of rotation 3b, is sekoitinparin 2 both mixers 3a, 3b impeller 5 blend direction parallel to, in this case, heavy, or the mixing-meth push mixable material enclosed in a direction having a spinner 4 downward pointing component.

In another embodiment, the mixer elements 5 have been prepared in such a way that the two stirrers sekoitinparin mixing the lifting direction, that is opposite to that in Fig. In a third embodiment, the first two sekoitinparin mixer impeller mixing direction is heavy and the lifting of the second mixer.

In one embodiment, the blade angle a is in the range 30 ° - 90 °. La-pakulman of 90 ° mixers are radial, straight onto the confounding mixers. Directly onto the mixing blades of the mixer is preferably mounted to the outer periphery of the circular plate, which can enhance disper for example, gas-liquid goitumista. Large turbulence at the point just blade angle of 90 °, and may also be caused vaakapyörteisyyttä below the circular plate, to which the dis-pergoitava gas is typically fed. Such a mixer may also be used, for example, speeding up chemical reactions.

Profiled shoulder and a propeller pitch, ie. the distance by which the mixer pushes the surrounding liquid during one kierrospyörähdyksensä, preferably in the bracket of 0.5 - 2.0 sekoitinhalkaisijaa. Sekoitinparien with respect to each other rotating in opposite directions mixers 3a and 3b mixing direction is either all, or heavy lifting.

According to an idea of ​​the number of impeller 5 1 - 4 for the mixer, and all four of the mixers, the blade angle is the same a or (180 - a) the selected area ° 15 ° - 165 °. When using more mixing element 5 on the same axis 4 are senior 5 impeller blade angles closer to the horizontal plane than the lower impeller 5 blade angles. Such an arrangement provides a blend of power allocated to the mixing volume of the bottom zone, wherein the solids can be prevented from landing on the bottom of the mixer and / or enhance the mixing of any additive such as a gas or disperse within the liquid-. Furthermore: a suitably selected blade angles can be enhanced sekoitinelinten cumulative effect of a mixture of, for example, by creating sekoitustilavuuteen uniform vertical flow. The top of the mixing with a suitable surface is obtained from the reactor self-priming gas, which together with the single vertical circulation results in a highly efficient mixing.

According to an idea part of the agitating member 5 is heavy or elevate and part of the radially confounding. For example, self-priming gas in the reactor can be a heavy upper mixer elements and deeper, the bottom zone-keeseen, made radiaalisekoitinelimet. The choice of the mixing means mixing the direction of influence, inter alia, the viscosity of the substance to be mixed.

According to the idea of ​​mixing means 5 is two per the mixer and mixing direction is heavy arrangement of all the mixers in the case of - fact remains that some of the lowest impeller blades lapakul-mana is 90 °, ie the mixer elements are radially confounding.. In such an application can be used, for example, already mentioned previously, the gls mixer. All sekoitinparien the upper mixer elements enhance the mixing heavy-direction lapakulmillaan, where a is selected from the range 25 ° - 35 °, respectively, and (180 - a) is in the range 155 ° -145 ° degrees.

According to a suoralapais-ten of the agitating mixers sekoitinparien the shoulder height of the lateral projection of view, in accordance with the idea of ​​a 1/8 - 1/4 the diameter of the agitating member. Shoulder to shoulder height to determine the mixer-men power draw: the higher the shoulder height, the greater the power output.

It is noted in this context that the use of sekoitinpariratkaisun substantially reduce the required sekoitinkehänopeutta. This in turn reduces loads on the mixers, the mixers may be used to lighter structures.

Each mixer can have its own drive motor 6 and the gear 7, as is the case shown in Fig embodiment. Use of engine 6 may be an electric motor and its power class is selected application-lutuskohtaisesti. The use of motors 6 can be controlled by per se known control means that are not described in further detail in this specification.

According to an idea of ​​each mixer 3a, 3b is arranged to be adjustable speed of rotation of the mixers 3a, 3b independently of the speed of rotation. Rotational speed difference may be, for example 0-30%. Sekoitinkohtaisella the rotational speed of adjustment can be achieved by a number of advantages. For example, increase or decrease the circulation volume, and thus to contribute to the flow velocity and turbulence either increase or decrease. The arrangement makes it possible to influence the distribution of the motor shaft power through through the circulation flow speed and turbulence as well as rotational speeds of the individual axes and those of any of the differences that the axes of the matched impeller characteristics. This can be optimized in the case of the mixing process capacity and product of this process, the quality of products.

In another embodiment, the sekoitinparilla 2 is a common drive motor and transmission.

Mixers 3a, 3b are arranged in the frame 8, which the käyttömootto-esters 6 and 7 gearboxes may be individually detachable. The frame 8 is typically a metal structure.

Mixer elements 5 are arranged sekoitinaltaaseen 9, which may be part of the casing 8 or alternatively separate from but here with respect to the bonded portion. Sekoitinallas 9 in this embodiment is a circular cylinder-shaped reactor is sealed and its material can be, for example metal.

Sekoitinparien mixers 3a, 3b and self sekoitinparit 2 sekoitinaltaaseen are grouped in accordance with rule 9 so as to provide effective use of covering the entire volume of the mixing pattern.

9 Sekoitinaltaassa no baffles, ie it is harmless. In other words, the inner surfaces of the mixer are free from material flow barriers.

Figure 2a shows schematically the general structure of a second arrangement from the side and partly in cross section, Figure 2b a top view in partial section, and Figure 2c a perspective view and partly in cross-section.

Arrangement one motor and gearbox solutions, as well as sekoitinallas are substantially similar to those of the previous figures.

Mixer elements 5 are here of the mixing helix comprising a tube formed by the coil 10.

10 of the coil-forming tube, or helix tube is the embodiment illustrated in Fig round, but this is by no means necessary as shown earlier in this specification: the pipe may be inter alia litis-assays and opened parts.

Coil 10 may be adapted to pass through a channel 11 which can be fed an additive blend. The additive is mostly gaseous, such as air or oxygen, but in some applications may of course also to make the liquid and / or solid state in the excipient. The additive can be used, for example, oxidation or reduction. The sprue discharge aperture 11 may be adapted, for example, helix-mixers sekoitinakse lin-4 and the lower part of the coil 11 connecting the support element 12 or the like.

It is noted in this connection that the feed channel 11 can be adapted to another type of mixing element, for example, blade mixer or radial mixers. Paddle the case of radial mixers and feed channel 11 may be arranged, for example, a mixer 4 and a discharge opening above and / or below or between the agitating blades of the mixer. Radial mixers discharge opening are arranged in the middle of the mixing of the circular plate and below it.

Helix-type mixer elements shown in Figure 5 comprises two spaced apart and parallel to the rotatable auger 10. Alternatively, 5 may be only one parallel helical, or three, or even more helix-type agitating member. Helix pitch angle of the tube is preferably in the range 8 ° - 60 °, and heliksputket rotate relative to each other and uniformly spaced-vakioetäi syydellä the mixer 4.

According to the idea of ​​helix tubes diverge in an upward vertical axis, for example at an angle of 5 ° - 30 °. Such an upward-expanding tapered kar-helix structure is particularly suitable for use in conical sekoitinaltaissa.

All of the mixers 3a, 3b, the direction is the mixing direction of the agitator 4, which raise the reason for the rise of the first mixer 3a of the agitating member 5 of the worm rotation direction is reversed with respect to the coil 5 of the second run 3b of the agitating mixer. Mixed Orientation may be selected differently -like this specification has already been established. In one embodiment, the helix-type range of the mixing ratio of the diameter of at least 1.0, preferably 3 to 10, and the agitator is in the direction of 2-6 parts, which cover 20% - 80% of the total height spiraalisekoittimen. In other words, between the successive parts of the spinner may be periods in which there is no mixing element. Despite this, the liquid can be stirred formed sufficiently strong vertical currents. By increasing the ratio of height to diameter achieve an increase in volume of the mixture of sizes. For example, such mixing means can be assembled separately manufactured modules. According to one idea, the module comprises a shaft section having a length of 3/2 with respect to, for example, the module of the mixing helix range. Such a construction facilitates the assembly of the mixing. The modules can be connected together, for example akselilaippaliitoksin.

Helix-type mixer elements are particularly suitable for handling slurries or dense fluid whose viscosity is high. Mixing direction is generally raising as mixers cumulative increase in the flow, it is preferable to get outside agitators. Further, the type of the mixing helix has the advantage that it can be implemented using a large height / diameter ratio, due to the high strength and stiffness of the structure.

In Figure 3 the general structure of a third arrangement is shown in schematic side view in partial cross-section. 1 arrangement is similar to that of Figure 1a, but here, unlike the lowermost I-5 of the mixing blend direction perpendicular to the agitator 4 ratio. Such a radi-aalityyppinen the mixing can be advantageous, for example, dispersing a gas containing solids slurry. Gas may be fed, for example, below the lowest impeller 5 and the center of the circular plate this plate.

It is noted in this context that the mixing can also comprise both radially and axially confounding bodies.

Impeller shaft 4 is thus provided with two mutually-different mixed insofar tinelin 5. The impeller shaft 4 for the same number of matched impeller 5 may of course be larger than two; as well impeller shaft 4 can be arranged three, four etc. different types of agitating member 5.

In one embodiment, four top of the agitator blade mixer is arranged to face a distance of 0.3 - 1.0, preferably 0.3 - 0.5, ittana expressed diameter of the mixer. Such a solution can be formed of the liquid to the surface a series of small vortices, through which the gas is absorbed by the mixture. This absorption of the gas mix can be further enhanced by adjusting the rotational speeds of the mixers, in certain cases, by adjusting the speed of rotation so that sekoitinparin 2 mixer 3a, 3b rotational speeds vary between 0-30%.

Figure 4 shows schematically a fourth arrangement and a method top view and partly in cross-section. The arrangement 1 comprises one sekoitinparin 2, which is arranged on a circular shaped sekoitinaltaaseen 9.

Sekoitinparin two mixers 3a, 3b of the shaft 4 is arranged symmetrically on both sides of the central axis of the circular cylinder M. Both of the mixer 3a, 3b mixer elements 5 have a diameter of preferably 25% - 40% of the diameter of a circular cylinder. It is noted that the mixer elements 5 is shown formed by the trajectory of the rotation means.

The inner surface of the mixer 9 is adapted to control the flow of osalieri-nts 13, which are disposed symmetrically mixers 3a, 3b ratio. 13-Osalieriöi the diameter is preferably 25% - 40% of the diameter of the mixer 9. Such an amount of solution is particularly advantageous for use in the blends can not be interrupted. Osalieriöiden 13 the effect can be seen particularly well maintained sufficient agitation even if one agitator 3a, 3b would be stopped incurred by it due to maintenance or replacement work. Osalieriön outer surface 13 can be presented not only as part of a circular cylinder-shaped portion of the polygonal cylindrical shape in Fig. The main flow direction is indicated by arrows F.

Figure 5 schematically shows a fifth arrangement and a method top view and partly in cross-section. This sekoitinallas 9-koitinakselien it comprises four arranged in parallel to the control element 14.

The control element 14 is shown in this embodiment, the shape of a circular cylinder. The control element 14 with the outer surface may comprise one or more flow controlling, flow controller 15.

According to one idea, the arrangement 1 comprises at least two mixer-pairs 2, which are arranged in a circular-shaped sekoitinaltaaseen 9 symmetrically mixer on either side of the central axis M, the diameter of 15% - 30% mixer 9 diameter, and a stirrer center is fitted a control element 14, the diameter of which is 15% - 25% of the diameter of the mixer.

According to one idea is that first a mixture of pairs of mutually the same first direction of rotation of the mixers 3a outermost extending impeller trajectory tangential to the mixer 9 the cylindrical enclosures, a distance of 3% - 10% mixer diameter, while others are mutually the same in the other direction rotating mixers 3b is positioned closer to the control element so that extending the outermost impeller this trajectory tangential to a distance of 3% -10% of the diameter of reaktorilieriön.

The solution according to Figure 5 may provide a number of advantages. First of all, the mixing can be balanced without a reactive braking baffles. Required for the mixing shaft power is low, but can be achieved by a mix of high volume-specific shaft power. The solution can be used in applications in which mixers can not be fitted in the middle a mixer such as, for example, thickeners supply wells, wherein the underflow of the cultivator and prevents the center axis of the mixer fitting. The reliability of the mixing process is good, because mixing can be maintained with only one other agitator is stopped, eg for maintenance work.

Figure 6 schematically shows a sixth arrangement and a method top view and partly in cross-section. This comprises three sekoitinpa- buffer 2 arranged on the shaped element 14 around the guide. This arrangement is particularly advantageous for the mixing volume is large. It is noted that the guiding element 14 can of course be shaped differently.

Figure 7a shows a schematic view of a seventh arrangement and a method top view and partly in cross-section.

The arrangement comprises four pieces of two sekoitinparin mixer 2 a four-forming sekoitinalueita 16 Sekoitinalueet 16 are grouped in a corresponding manner with each other as sekoitinalueen 16 form four mixers are grouped. In this way, a comprehensive sixteen obtained from the mixer 3a, 3b grouping a sekoitinkonstellaatio.

Each sekoitinalue 16 comprises a control element 14, which is adapted to sekoitinalueen 16 to the center. The mixer 9 is also adapted to center the guide element 14.

Figure 7b shows schematically the arrangement and method of Figure 7a, another embodiment of a top view in partial cross-section. The difference between the solution according to Figure 7a is that the two-sekoitinpariryhmi tyksen mixers directions of rotation are opposite.

Comparing Figures 7a and 7b solutions to each other can be stated that the solution of 7a of Fig achieved due to the symmetric-flows caused by two sekoitinpariryhmityksen which either come from opposite directions circumferential spaces between the two mixing pair, or the like absorbed in opposite directions away from these facilities restrained counter-clockwise kehävirtaukseen. Instead of Figure 7b is achieved by the solution according to a well-developed and powerful figure counter-clockwise oriented, Wed-hävirtaus and another powerful clockwise-oriented center of the flow. In particular, the solution according to figure 7b is also well suited for use in natural waters.

Figure 8 shows schematically an eighth arrangement and a method and a top part 1 comprises eight poikkileikattuna.Järjestely sekoitinpareja two pieces, which are therefore a total of sixteen mixer 3a, 3b. Sekoitinparit 2 is arranged in a flat cylindrical sekoitinaltaaseen 9 - unlike that of Figures 7a, 7b, which are arranged sekoitinparit first two sekoitinparista formed in a sekoitinalueeseen.

Two sekoitinparia 2 in a square array the center of the mixing space 14 around the control element and six sekoitinparia 2 is in turn 9 in the vicinity of the periphery of the mixer close to each other.

Each sekoitinalue 16 comprises a control element 14, which is adapted to sekoitinalueen 16 to the center. Sekoitinaltaaseen 9 is arranged in nine pieces of control elements 14, one of which is a mixer 9 in the center of the center and the other eight circulating peripheral formation.

Comparing Figures 7a, 7b and 8 of the solutions presented by each other can be stated that the solution of Figure 8 provides even more uniform mixing pattern, making it possible to reduce the overall intensity of mixing. In addition, the entire contents of mixer 9 counter-clockwise This flow is more restrained than that of Figure 7a, 7b solution. The arrangement of the Figure 8 provides a strong rotational flow. FIGURES 7a, 7b, and 8 according to the solutions can be reduced to large, for example 5000 - 20 000 m3 volumes, for a total mixing power needed.

Figure 9 shows schematically a ninth arrangement and a method top view and partly in cross-section. This rectangular-shaped sekoitinallas 9 is an example of polygon-shaped cross-section sekoitinaltaasta. It can be closed or open at the top. The mixer 9 a polygonal shape may also be a square or a five-, six-, etc. angle. Four sekoitinparia 2 neliöryhmitykseen 14 is arranged around three guide element. Mixers 3a, 3b, and in particular formed by covering the entire flow volume to be mixed.

Mixers can be arranged in one or more sekoitinparirivi as a polygon-shaped sekoitinaltaaseen 9 9 Sekoitinaltaassa increased flow rate by a rotary single- or multi-part raising or lowering the same in the direction of the rotation speed of the rotary mixers in the opposite direction to the rotation speed of the rotation of the mixers.

Sekoitinallas 9 is shown in dashed lines intended to highlight the arrangement and method embodiment, in which sekoitinpari adapted to the natural sekoitinaltaaseen, such as a pond, lake, river or the sea, or built into the pool water such as a dam or pond water treatment plant for water treatment tank. In other words, separately prepared sekoitinallas 9 does not have nor a necessary part of the process.

Figure 10 is a schematic view of a structure of the mixing cross section. Helix 10 of the mixing coil-forming tube 17 is flattened in FIG 50%, i. d is the diameter value of the initial half of the circular tube in diameter D. Litistyssuunta coincides direction of the agitator, or alternatively translated 0 ° - 30 ° from this direction. In the latter solution, the stirrer effect of the flow is directed more strongly mixing tank circumference. Helikssekoittimen the ratio of the diameter of the tube 17 the diameter of the helix of the mixer according to an idea of ​​a range of 0.03 - 0.08. At the dimensioning of the impeller leads to a particularly preferred tehonot-to the agitating rotation speed of 2-6 m / s.

Figure 11 shows schematically a second cross-sectional structure of the mixing. Helix of the mixing of the coil 10 forming the wall of the tube 17 is open at 02 and at 08 between.

Figure 12a shows schematically the general structure of a tenth arrangement is a partly cross-sectional view and a top view in Figure 12b.

The arrangement 1 comprises two sekoitinparia two, or four mixer 3a, 3b. An arrangement may be immersed in the liquid, which is shown on a liquid surface S. Arrangement with respect to the liquid surface S may be another.

Each mixer element of the mixer 5 is housed in its own vertically arranged sekoitinputkeensa 18 Sekoitinputken 18, the inner diameter may be, for example, 5 - 15% bigger than the diameter of the mixers. Sekoitinputki 18 may extend, for example, one - three dimensionally distance x below the diameter of the mixers. This can be achieved by a very powerful direct downward flow, which are linked together kartiosupistuksessa 23 and will continue at an accelerating pace down pystylieriöputkea 19 pairs against each other to rotate in Discrete-currents caused by its contracting downflow strong turbulence, which can be dispersed in large amounts of the additive.

According to one idea of ​​the mixer elements are five types of marin-it-mixer element, or propellers, axial or foil-type-loivalapaisia ​​the mixing methods, where the blade angle a is for example, from 10 ° - 30 ° relative to the horizontal. Such mixer elements cause the axial currents that are advantageous with respect to achieving the power input for maximum vertical current Meeting.

Mixer elements 5 are arranged to rotate in such a way that they push the liquid to be mixed down pystylieriöputkeen 19 feet. The mixers downward trends combine with each other pystylieriöputkessa 19 having a diameter of 80 to 100% greater than the diameter of the sekoitinputken 18.

According to one idea, the pystylieriöputken 19 flow area may be, for example, 15% - 30% less than 18 in one of four sekoitinputken las fox flow area. In this case, flowing pystyiieriöputkeen 19 liquid comes into accelerating motion. The combined flow rate may be for example 0.8 m / s -1.6 m / s. At the point where the streams combine the mixers can be fed an additive already set out above. Downflow lead to an accelerating additive, for example, a gas such as air or oxygen, flows deep into the pystylieriöputkea bubbles 19 into the surrounding liquid. The arrangement can lead to turbulent flow of liquid deep into the terms of the arrangement outside the reactor or a natural body of water.

The liquid can return to the held sekoitinputkiin 19 from the return channel 18 pystylieriöputken 20, conical section 21 and ylälieriön through 22. The liquid level is typically above 18 sekoitinputkien. 20 The length of the return channel in relation to the length of pystylieriöputken 19 can be completely different from the graph: for example, their lower parts can extend the same horizontal level. Return to Channel 20 the length of the range is illustrated by the arrow 20 A. The length of the return channel can be set by adjusting the level at which the liquid is sucked sekoitinputkiin 18.

Figure 13 is a schematic view of a general structure of the eleventh arrangement from the side and partly in cross-section. This solution differs from the figures 12a, 12b according to the decision that there is no return channel 20, the conical part 21 and the lead 22. ylälieriötä Sekoitinputkiin 18 into the liquid from above, to yield the mixed fluid in the vicinity of the liquid surface and fed into the deeper. Such a solution is well suited, inter alia, for use in natural waters.

Figures 12a and 13 presented solution is particularly advantageous when dealing with large currents in large-size rotary vertical arrangement, ie. With a capacity of at least the order of 1000 m3. In such an arrangement can be mixed insofar-keeper means 5 in diameter must be less than 4000 mm and the engine size of less than 300 kW, which makes it possible to avoid heavy and costly vetopäärakenteilta. A further advantage is the improved reliability already said. The solution is well suited for processes in which the liquid comprises a slurry in which the slurry is fed oxygen to promote dissolution. Oxygen is fed as described above sekoitinputkien preferably below 18, that is, the place where the above-mentioned osavirtauk-set to coincide with each other. Oxygen is dispersed effectively down at high speed, for example more than 1 m / s stream of the slurry. Kuplaston against the nos tesuuntaa slurry flowing kuplastoon cause oscillation, thus speeding up the dissolving of oxygen in the digestion and oxygen. Even in this case, it is preferred that the propeller pairs rotate in opposite directions, which accelerates the oxygen-dispersing turbulence tumista pystylieriöputken 19 at the top of downflow acceleration. In addition, the taper portion 23 strengthens the central flow pystylieriöputken central portion 19, with the result that in the vicinity of the wall 19 pystylieriöputken generated lisäpyörteisyyttä form päästöpyörteisyyden and evening out the flow proceeds pystylieriöputkessa 19.

It is noted that the solution according to Figure 12a can be used, for example, to ensure a steady supply of liquid sekoitinputkiin. kartiorakenteil-la can reduce the pressure losses caused by fluid yläkäännöksestä, which contribute to increase the flow down.

Figure 14 shows schematically the general structure of a Twelfth arrangement from the side and partly in cross-section. Sekoitinputket 18 is arranged in its entirety below the liquid surface S, for example, so that their distance from the liquid surface S is sekoitinputken relative to the inner diameter of 1.0 - 3 times. In this case, the upper ends of sekoitinputkien are so far below the surface, it is ensured that the sekoitinputkeen steady flow of fluid in each. It is noted that the solution according to Figure 13 away from the liquid surface S is preferably arranged in the same way.

The solution shown in Figure 12a differs most substantially in that the structure is carried out without ylälieriötä 22. As a result, sekoitinputkiin 18 lead into the top of the liquid to be mixed in the vicinity of the liquid surface of the liquid and fed into the deeper. Such a solution is well suited, inter alia, for use in natural waters.

Figures 15a - 15c are schematic representations of some of the natural water flow, such as a strait, channel, ditch, stream, river, etc.-ordinated arrangements from above.. These mixers shown in Figures 3a, 3b are preferably helix-mixers, which are arranged to rotate in the direction of the lifting mixing. Helix, for example for mixing and stirring paddle mixer can be used.

The arrangements further comprise at least one dispensing point 23. At this point the flow is fed to appropriate one or more additives, examples of which have already been mentioned earlier in this specification. According to one idea of ​​the ferric sulphate is administered, the water is removed by means of which the phosphorus.

In the solution shown in Figure 15a is one sekoitinpari two and one dosing point 23. The metering point 23 is preferably located slightly upstream relative to the center and two sekoitinparin.

In the solution shown in Figure 15b has two and two sekoitinparia one dosing point 23.

In the solution shown in Figure 15c has three and two sekoitinparia one dosing point 23 towards each sekoitinparia.

The drawings and the related description are only intended to illustrate the invention. Those skilled in the art will appreciate that the invention is not limited to the embodiments described above, the invention has been described with some examples, but many variations and different embodiments of the invention are possible in the claims presented below within the framework of the inventive idea.

Reference numerals 1 Arrangement 2 sekoitinpari 3a, 3b mixer 4 agitator 5 mixing means 6 drive motor 7 gearbox 8 frame 9 sekoitinallas 10 coil 11 of the supply channel 12 the support element 13 osalieriö 14 control element 15 flow controller 16 sekoitinalue 17 of the tube 18 sekoitinputki 19 pystylieriöputki 20 return channel 21 the conical portion 22 ylälieriö 23 inner cone section 24 of the dispensing point A suction surface adjustment D, d the diameter dimension F the main flow direction of the center axis M S surface

Claims (17)

An arrangement for mixing a liquid, the arrangement (1) comprising at least one agitator pair (2), said agitator pair (2) having a first and a second agitator (3a, 3b) whose agitator shafts (4) are arranged vertically, parallel to each other and rotating in opposite directions, the first and second agitators (3a, 3b) comprising at least one agitating means (5) provided to the agitator shaft (4), said agitating means (5) being arranged in an agitator cistern (9) which is free of flow obstacles , i.e. vertical disks attached to the wall of the agitator (9), which agitator (9) is circularly cylindrical or rectangular, and the agitator shafts (4) are spaced from the center of said circular cylinder or in a rectangular agitator (9) at a distance from its center line characterized in that the direction of agitation of the agitator means (5) of both agitators in the agitator pair (2) is pushing or lifting, the partial currents and swirls of the agitator pair (2) cumulatively intensifying each other and in the liquid to be agitated a stirring pattern extending over the whole the effective use volume of the stir bar (9). Arrangement according to claim 1, characterized in that each agitator (3a, 3b) has its own operating motor (6). Arrangement according to claim 1 or 2, characterized in that the rotational speed of each stirrer (3a, 3b) is arranged to be controlled independently of the rotational speed of other stirrer (3a, 3b). Arrangement according to one of the preceding claims, characterized in that the stirrer (5) is dimensioned and arranged in such a way that it does not overlap the stirrer (5) of the second stirrer (3a, 3) in the stirrer pair (2). 5. Arrangement according to claim 4, characterized in that the agitator cistern (9) comprises a cylindrical guide element (14) arranged between two agitators (3a, 3b) and parallel to the agitator shafts (4) and whose outer surface may comprise a flow controls (15) controlling the flow. Arrangement according to claim 4 or 5, characterized in that the agitator (9) is circularly cylindrical and the agitator shafts (4) of the agitators (3a, 3b) are arranged at the same distance from the center of the circular cylinder. Arrangement according to claim 4 or 5, characterized in that the agitator (9) is circularly cylindrical and the agitator shafts (4) of the agitators (3a, 3b) are arranged at different distances from the center of the circular cylinder. Arrangement according to one of the preceding claims, characterized in that it comprises at least two stirring pairs (2). Arrangement according to one of the preceding claims, characterized in that two mutually different stirring means are arranged on the same stirrer shaft (4). Arrangement according to claim 1, characterized in that it comprises a stirrer pair (2) installed in the circular cylindrical stirrer cistern (9), that the stirrers (3a, 3b) with their stirrer shafts (4) are symmetrically installed on each side of the stirrer. the central axis (M) of the circular cylinder, that the diameter of the stirrer (5) is 25% - 40% of the diameter of the stirrer (9), that sub-cylinders (13) are arranged on the inner surface of the stirrer (9) which control the flow and are arranged symmetrically in relation to the flow. to the agitators (3a, 3b) and that the diameter of the sub-cylinders (13) is 25% - 40% of the diameter of the agitator (9). Arrangement according to claim 1, characterized in that it comprises two stirrer pairs (2) installed in the circular cylindrical stirrer basin (9), that the stirrer (3a, 3b) with its stirrer shafts (4) is symmetrically located on each side of the center shaft (M) of the agitator cistern and having a diameter which is 15% - 30% of the diameter of the agitating cistern (9) and that the center of the agitating cistern (9) comprises a circular cylindrical guide element (14) whose diameter is 15% - 25% of the diameter. the diameter of the stir bar (9). Arrangement according to claim 1, characterized in that in the first, rotating outer agitator (3a), rotating in the first, rotating outer stirrer (3a) within an area extending towards the circular cylinder of the stirrer cistern (9). % - 10% of the diameter of the stirrer cistern, that the center of the stirrer cistern (9) comprises a circular cylindrical guide element (14) whose diameter is 15% - 25% of the diameter of the stirrer cistern (9) and that the other, in the same other direction, rotate the stirrer (3b) ) are positioned closer to the control element (14) in such a way that the area of movement of their outer stirrer means tangles this element (14) at a distance of 3% -10% of the diameter of the stirrer cistern (9). Arrangement according to one of Claims 1 to 4, characterized in that the two stirrers (3a, 3b) of the stirrer pair are arranged in their respective stirrers (18) which are arranged vertically, that the stirring direction of the stirrers (3a, 3b) is pushing and that the stirrer tubes ( 18) the lower end opens to the lower end of an inner condenser (23) and further to the lower portion (19) of the vertical circulation, from which a return channel (20) is arranged above the stirring tubes (18). 14. Arrangement according to claim 13, characterized in that the agitators (3a, 3b) comprise agitator means (5) which are of the marine type, the axial type of the foil type or the members with a slightly inclined blade. A method of stirring a liquid, in which method: the liquid to be stirred is arranged in stirring volume, the stirring volume being stirred with at least one stirring pair (2) in a stirring cistern (9) free of flow obstacles, i.e. vertical slices fixed to the wall of the stirrer cistern (9), wherein the stirrer shafts (4) of the stirrer pair (2) are arranged vertically and rotated in parallel but in opposite directions, the stirring volume comprising a circular cylindrical or rectangular stirrer cistern (9). arranged at a distance from the center of said circular cylinder or in a rectangular agitator (9) at a distance from its center line, characterized in that the direction of agitation of both agitator means (5) of the agitator pair (2) is pushing or lifting, the partial currents and The swirls formed by the stirrer pair (2) cumulatively intensify each other and in the liquid to be stirred, a stirring configuration is created which extends over the entire effective volume of the stir bar (9). 16. A process according to claim 15, characterized in that an additive is added to the liquid to be stirred through a feeder channel (11) arranged in the stirrer (5). Method according to Claim 15 or 16, characterized in that the rotational speeds of the agitators (3a, 3b) are controlled independently of the rotational speeds of the other agitators (3a, 3b).