DE1757999A1 - Mixing and homogenizing device - Google Patents

Description

The invention relates to a mixing and homogenizing device for powdered solids, of which at least one is not able to flow freely} According to the invention, the advantages of a batchwise operating incinerator combined with those of a continuously operating mixer, while at the same time the disadvantages of the two types of Mixers are avoided. The device according to the invention is particularly suitable for mixing extremely fine-grained powdery Fabrics

There are several types of batch-type mixers for solids known, the batch mixers are referred to briefly as ₀ A common feature of such batch mixers ueaüeuc Aarin that the introduction of the materials to be mixed and the removal of the mixture produced intermittently causes "These Batch mixers include, for example, numerous types of rotatable

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Mixers (double cone, Y / cube, V and Y mixers), furthermore Mixers with agitators (planetary gear mixers, mixers with plows, knives, spiral or helical components and kneading devices), ball mills, pan mills, ribbon mixers, etc.

Comparatively speaking, only a significantly lower number of continuously operating mixers stands for solid fabrics available. In many cases the batch mixers are suitably modified. A common one The feature of these mixers is that filling and emptying are continuous. Examples of such continuously operating mixers are modified ball mills, Pan mixers and ribbon mixers as well as screw mixers and zigzag mixers are called.

In practice, the choice between batch and continuous mixers will primarily be based on the amount of material being processed, and it should be noted that the use of continuous mixers is most appropriate when processing large quantities of material. However, theoretically it I3T preferable choice to meet to be used mixer taking into account the quality of the required mixing action and not the quantity throughput · To better understand the invention, an overview is given of the advantages and disadvantages of the two mixer types below _t in particular mixing solid of Substances are taken into account, of which at least one is not able to flow freely. 109825/0439

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The advantages of batch mixers are that the substances to be mixed can be easily dosed, that they are suitable for both large and small amounts of material, that the duration of the Liisclivor ^ angs can be easily regulated, and that iu π η for their operation No trained staff is required o Generally speaking, batch mixers can easily be adapted to special operating conditions in terms of temperature, pressure, keeping away from oxygen or operation under sterile conditions o In particular with small mixers, it is not difficult to make a sufficient volume available it is a batch mixer !! about comparatively cheap machines.

The guard parts of the cage mixer are that the There is always the risk of dead spaces occurring, so there is no guarantee that all individual quantities of the materials will be equally intense are mixed, and that energy is wasted as unmixed or not enough ingredients mixed as well the finished mixture is exposed to the mixing effect in the same manner v / earth. As a result, the duration of the visual process is often prolonged, and in some cases to such an extent that that the quality of the equipment is impaired, and even before the components are sufficiently evenly distributed in one another «. In general there is for the greetings of the individual batches oiner; optimal value that is only marginally may be exceeded or undercut.

The advantages of the continuously operating machines

steu in that uolebe Irish very gi'oije; .materialr; e / if: eii

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can process that all individual quantities are intensively mixed, and that the mixture produced is continuous can be carried away «, The duration of the mixing process, i.e. the time during which the material to be treated remains in the mixing part of the device is often short. The influence of dead spaces is less than with Ohargenmi books

With regard to the disadvantages of the continuously operating mixer, it should be noted that the uniformity of the dosage of the constituents is decisive for the quality of the mixture · Because the Geraisch constituents or at least a part of them are not able to flow freely, a uniform dosage can be effected only with difficulty, and therefore caused the right dosage high cost. Perfect mixing is almost impossible with small amounts of material. From this This results in the basic rule, which says that continuously working mixers are used for solids that cannot flow freely can only be used successfully with very large amounts of material. Also attempts that with continuously working mixers are costly. The only alternative is to try using Batch mixers, but such experiments are of course not very informative. Mixing in vacuum, under Pressure or under sterile conditions proves to be very difficult. Operation requires continuously operating mixers in most cases some professional knowledge,

From the above overview it can be seen that the

continuously working mixer and the batch mixer almost

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ügLioh jedoa differ, i / aa differ in the can achieve a type of construction without difficulty, Lot at the other design difficult or impossible, and vice versa »v / enri e3 succeed v / uld, a device for mixing not freely flowable to create solid materials in which the advantages of both types are combined and their disadvantages are avoided, thus a remarkable technical advance was made in this the field of production of mixtures exist,

The main feature of all continuously working mixers does not consist in the way in which the mix is fed in and removed, nor in its suitability for processing large amounts of material, '»/ as for those who work continuously Mixer is characteristic is the fact that the material fed in as a whole passes through the mixing or homogenizing zone. Therefore it is more correct to use a continuous mixer and not to speak of a continuously working mixer »

The device according to the invention is such a continuous mixer, i.e. a so-called continuous working mixer for not free-flowing powdery substances. The mixer according to the invention can both operated continuously to make great MaterLalmengön process, a is also as a batch mixer, if only small amounts of material come into question, Dia is now no such device known

The result of this is the fulfillment of the requirements characterized that ο he at least one generally timed

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Shaped assembly comprising two conical mixing chambers consists, which are separated from each other by plates or sieves; the device further comprises a drivable shaft which extends axially and centrally through the assembly and in each chamber on either side of the plates or sieves carries at least one agitator that is in the same Direction rotates, as well as at least one friction device, e.g. a brush that also revolves in the same direction and is pressed against the plates or screens o

A first embodiment of this device is through a generally hourglass-shaped assembly of two of the same type marked conical chambers; this assembly can be at least at the level of the plates or sieves mentioned around a transverse axis Be swiveled 180 °. If this assembly is swiveled through 180 °, the mixing process can be repeated.

The mentioned assembly can be pivotably mounted in a frame. On the perforated plate or sieve facing away, each mixing chamber can be provided with an at least partially transparent cover »

Another possible embodiment of the invention Apparatus is characterized in that several generally hourglass-shaped assemblies are arranged on top of one another and so rear edges are switched; here is the lower end of the lower chamber of each assembly connected to the upper end of the upper chamber of the next assembly below, and between adjacent chambers or assemblies are rewarded

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Plates or sieves arranged, and on either side of each On the plate or each sieve, a friction device, e.g. a brush, is brought into action. In this embodiment is it is no longer necessary to swivel the mixing device «. This embodiment of the invention is particularly suitable for processing larger quantities of material. It would be necessary to process such quantities with the aid of a pivoting assembly make to provide a very heavy construction.

Measures that can be applied in both embodiments described are that the friction devices, the compressive forces apply to each side of the perforated plates or screens, are not arranged opposite one another, and that the drivable shaft together with the entire device can be brought into a position in which it does not extend in a perpendicular direction «The first measure leads to ensure that the mix is evenly promoted through the perforated plates or sieves, and the second measure is the Possibility to set the dwell time of the mix in each of the chambers. "

The agitator blades or the like can be arranged on a bushing which is attached to the centrally arranged drive shaft is pushed open and rotatably connected to it. The agitating elements can essentially all parts of the contents of the Chambers come into contact} they can be in the most varied. Form, e.g. in the form of wires, blades or knives. Their shape can be chosen so that the material

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is whirled up or pushed down in the chambers. The friction devices or brushes can also differ with regard to their Different shape, and it is possible to use different materials of different hardness. The friction devices or brushes are either on a stirrer or on one loose ring attached, which is pushed onto the central drive shaft and is non-rotatably connected to it · The agitator elements and the friction devices are interchangeable and preferably are Measures have been taken to enable the speed of rotation of the Y / elle to vary within wide limits for what purpose the speed of the motor and / or the gearbox is changed accordingly.

In the device according to the invention there is a to now not given number of possibilities for regulating the intensity of the mixing process; therefore it is according to the invention possible to meet the requirements regarding the quality of the mixture in every respect, which is not possible until now.

With a mixer according to the invention, it is possible to regulate and set the mode of operation by various measures. Firstly, it is possible to vary the number of revolutions per minute; secondly, the mesh size of the sieve and the ratio between the opening area and the total area of the sieve can be varied; the total area depends primarily on the materials and the construction of the screen; thirdly, the shape of the agitator can be varied; the validity of pre-mixing in the upper chamber and the Nachmischens in the lower chamber is determined ;, fourthly can be the shape and the _tool;

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- Q -

3toff dor friction devices vary; for example, the Brushes v / calibrated or hard and provided with short or long bristles and it is also possible to use a scraper, e.g. from the under the legally protected designation Teflon is made of the material available} Fifthly, one can use the option vary the device; at a large angle of inclination if the duration of the mixing process is of course considerably lengthened, the number of passes of the materials can be avoided vary, with the number of passes in the second Embodiment depends on the number of modules used.

It is possible to choose the optimal conditions for each mixture, and in many cases one can choose between numerous possibilities. For example, in Crumisoh one can produce a precisely determined quality grade, Liutiiii, for example _, a fine-meshed sieve and a hard brush are used, with the insulating shaft inclined at an angle of 30 ° and the material passing through the mixer Z7 / once the same quality grade ₀ B. could be achieved Z, when using a less fine mesh Üieb when the üJischerwelle is arranged vertically, and when <iaa material passes through the mixer four times. For '/ eruche in particular, it is important that the degree of filling of the mixer plays as little hell as possible, in contrast to numerous known batch mixers, in which a deviation iron from the optimal batch soon leads to a reduction in the degree.

Similar to the second embodiment described above, 3-form it should be noted that, of course, the periods of time during which the contents remain in the various chambers.

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must be coordinated so that a uniform material throughput is guaranteed; the construction of the sieve plays a role here. the mesh size plays an important role. All These factors can be determined empirically and experiments with the pivotable embodiment can also be carried out employ who work according to the same basic idea. If the differences are not too great when the mix is not fed in continuously, it is possible to do so continuously to discharge an even mixture from the device «If it is possible to dose the substances more evenly, one can get by with a smaller number of chambers.

Comparison / requests with mixtures of various compositions, which were carried out both with a device according to the invention and with devices of a known type, which differed largely in terms of their construction, showed that the device according to the invention the known Devices is considerably superior «

In a device according to the invention, constituents of the substances to be mixed can optionally be replaced by small amounts of liquid are formed.

The invention is illustrated more schematically below with reference to the hand Drawings on several exemplary embodiments explained in more detail «

Fig. 1 shows a reversible device according to the invention in a longitudinal section.

Fig. 2 is a longitudinal section through a non-reversible one Device according to the invention »

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The substances to be mixed are combined with one another in the conical upper chamber, the chamber is closed with the lid 1 locked, and then the engine 2 is started. The motor 2 drives a shaft 3 »with which the agitators 4 and the brushes 5 are rotatably connected, at a preselected speed. The substances are premixed by the upper stirrer, and agglomerated material is ground on the sieve 6. The entire amount of material is pressed through the sieve; the brush 5 in the lower chamber causes constant cleaning of the sieve; advantageous effects result from this. The material to be mixed is then taken up by the second chamber in order, as shown in FIG. 1, to be mixed again in this chamber by the agitator 4 to become ο

In this context it should be noted that the Y / echsel between a large diameter and a small diameter, as is characteristic of the hourglass shape described, has a beneficial effect. The material that is initially in the narrowest part of the upper chamber moves to the widest part of the second chamber, and vice versa. In this way the material is additionally spread out «

When the entire material has passed the first sieve 6 in the construction according to FIG. 1, the device is pivoted through 180 ° with the aid of the transverse shaft 8, the support frame 7 also being pivoted accordingly. The motor 2 also takes part in this pivoting movement. The second chamber is now at the top, and this material is moved again and pushed through the sieve. These work steps can be like this

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be repeated often »as is necessary to achieve a sufficiently homogeneous mixture · The viewing window 9 into the Covers 1 of the chambers make it possible to monitor the mixing process 2u! In addition, each cover can be closed with a » bai'en opening, so that the chambers material - can take samples

The ^{embodiment shown in Fig. 1 (} Fig. 2) comprises a plurality of generally hourglass-shaped assemblies arranged one above the other and thus connected in series. As shown in Fig. 2, the lower end of the lower chamber of each assembly is connected to the upper end of the upper chamber of the assembly arranged below; A perforated plate or a sieve 10 is arranged between each two adjacent chambers, and a friction device, for example a brush 11, is provided on both sides of each sieve.

In contrast to the drawings, the friction devices can also be designed so that they extend diametrically over the entire sieve! here the friction devices are, for example, arranged at right angles to the agitator 4

It should be superfluous to describe in what way the finished mixture of the device according to the invention can be taken.

£ atentans, prüchejt 109825 / 0A39

Claims (1)

Mixing and homogenizing device for pulverfb'r mige solid substances, of which at least one is not free-flowing, characterized by at least one generally hourglass-shaped assembly of two conical mixing chambers, between which perforated plates or sieves (6) are arranged, a drivable shaft (3), the üich along the central axis of the Assembly extends and in each chamber on both sides of the perforated plate or »the sieve carries at least one agitator (4) that rotates in the same direction, as well as at least one friction device, ζ.B ₀ a brush (5), which also rotates in the same direction and is pressed against the perforated plate or »the sieve» 2 ο device according to claim 1, characterized in that the Reibvorriclitungen which against both Sides of the perforated plate or the sieve are pressed, are not arranged opposite one another. 3. Device according to claim 1 or 2, characterized in that the drivable // part is adjustable and can be arranged so that it extends at an angle to the vertical. ....., ... ,, 109825/0439 4. Device according to one of claims 1 to 3, characterized by a generally hourglass-shaped Assembly of two conical chambers of the same type, which are mounted in this way is that it is level with the perforated plate or the Sieve can be swiveled by at least 180 ° around a horizontal axis » 5. Apparatus according to claim 1 to 3, characterized in that g e k e η η draws that several generally hourglass-shaped assemblies arranged one on top of the other or connected in series, the lower end of the lower chamber of each assembly with the upper end of the upper chamber of the next one below Assembly is connected, and that a perforated plate or a sieve is arranged between each two adjacent chambers a friction device, e.g. a brush, is arranged on each of the two discs of the plate or the 3 sieves. 1Q9825 / 0439 BATH ORIGINAL ft . L e r s e i ί e