EP0672449A1 - Method and device for preparing a slurry, emulsioning or/and grinding - Google Patents

Abstract

A process and assembly (A, B) grinds and converts substances into sludge or emulsions. The starting substances consist of solid particles, solid particles and a fluid, solid particles and several immiscible fluids, or several normally immiscible fluids. The twin assembly (A, B) incorporates a grinding point (MS) at which the substances are ground in a converging gap between two surface areas (MA, MB) rotating about axes (X, Y). The novelty is that the substances being processed are brought to the grinding point (MS) and the necessary pressure forces are generated, by the surfaces (MA, MB) as they move together from the same side to the grinding point (MS). The two grinding surfaces (MA, MB) pass through the grinding point (MS) at different rotational speeds. The forces deforming the substances are generated in the vicinity of the grinding point (MS) by a combination of opposing concave and convex surfaces.

Description

The invention is in the field of grinding and mixing technology and relates to a method and a device according to the preambles of the corresponding independent claims for slurrying, emulsifying and / or grinding, in particular for very gentle slurrying, emulsifying and / or grinding, which Particularly suitable for highly sensitive plant and animal, solid and / or liquid material.

In the following, slurries are used to denote a process in which a macroscopically homogeneous slurry (slurry) is created from a mixture of solid parts and liquid while comminuting the solid parts. Emulsification is a process in which a macroscopically homogeneous emulsion is made from areas of immiscible liquids.

There are various methods for mixing and grinding inhomogeneous mixtures consisting of solid parts (e.g. plant parts such as leaves, stems or parts of roots) and a liquid (eg water), that a relatively homogeneous and relatively stable slurry is formed in the form of a slurry that can be used for further processing purposes.

For example, the plant material alone is finely chopped using a high-speed cutting machine, such as is used for chopping meat, and the resulting chopped material is used for further processing, e.g. Fermentation or fermentation, mixed with the liquid. You can also process plant parts with a hand blender in a container directly with the addition of a liquid to a pulp.

However, especially when processing fresh parts of plants, it has been shown that such known methods have considerable disadvantages. For example, if you want to make preparations from fresh plants, it is not only important to grind the plants or parts of plants sufficiently fine, but it must also be ensured that, for example, the active and aromatic substances are released. By chopping with high-speed, sharp-edged knife wheels or high-speed mixers, the fine structures are often insufficiently unlocked to release the desired substances, e.g. only those cells are broken open that are currently on the cutting edge, while the others remain intact and do not release the substances.

Another disadvantage is that the plant material is locally heated by high speeds, ie high tool speeds, and the quality of the product can be impaired as a result.

Emulsions are also produced by crushing the drops of the various immiscible liquids with high-speed, often sharp tools, the local heating, in particular when processing highly viscous and highly sensitive liquids, such as e.g. Protein, can also be a problem.

The problems mentioned above occur less if a mortar consisting of a mortar bowl and pestle is used to crush highly sensitive materials by hand and with the force and speed adapted to the material. The preparation of plant materials with the mortar, however, requires a lot of time and an enormous physical achievement of the person. In addition, the material must be pre-shredded for processing in the mortar.

European patent application No. A2 0 040 182 also describes a motor-driven mortar in which a heavy grinding element (pestle) in the form of a roller or a cone, which rolls freely in the grinding vessel, lies in a rotating grinding vessel (mortar bowl) the material is crushed between the grinding vessel and the grinding media. With such a mortar, it can be ground (ground) gently, but not slurried and emulsified.

The object of the invention is therefore to demonstrate a method and to provide an apparatus for carrying out the method, using which mixtures consisting of solid parts and liquid, consisting of solid parts and several immiscible liquids or consisting of immiscible liquids are possible in one work step homogeneous slurries or emulsions can be processed, but can also be used to grind solid substances. The method and device should be particularly advantageously applicable for highly sensitive materials. The sensitive components should not be damaged by local heating. Furthermore, the fine structures are to be processed in such a way that the most intensive possible interaction between the individual parts of the materials to be processed is made possible, so that, for example, soluble components pass as completely as possible into the liquid. The device according to the invention should be particularly advantageously applicable for gentle processing of highly sensitive, vegetable and animal materials. It should also be applicable for fibrous and tough solid parts and for highly viscous liquids. The device according to the invention should also be designed such that it is largely independent of the container in which the material to be processed is contained and that it can be easily adapted to different applications.

This object is achieved by the method and the device as defined in the patent claims.

According to the method according to the invention, rhythmically pressing forces, deformation forces and shear forces are exerted on the solid parts or drops of the material to be crushed in a rhythmically changing grinding / stirring process, the force action being rhythmically interrupted by dwell times in the liquid. The force of the solid parts is crushed in a grinding manner, i.e. actually crushed, stretched and torn (not cut), while liquid, which adheres to the solid surface and / or has penetrated into the solid parts, is pressed out with substances dissolved in it. During the dwell times, the squeezed liquid is replaced and newly created surfaces are wetted by squeezing and tearing and / or newly accessible areas of the interior of the solid parts are brought into interaction with liquid.

The above explanations for drops can be used accordingly for the preparation of emulsions. The interaction with the liquid is eliminated for a pure grinding process.

The device according to the invention is inspired by the natural process of chewing, as is carried out in particular by cows ruminating. Plants or parts of plants are pressed, ground and torn between the chewing surfaces of the teeth, which have mating bumps and hollows, and mixed with saliva in the mouth. The plant material is not only macroscopically crushed, but also microscopic structures are opened, so that, for example, active ingredients and flavorings are accessible. It can be observed that the cow performs this chewing process rhythmically. One has to conclude from this that the change between active chewing between the teeth and the relaxing movement in the mouth (e.g. through the tongue) makes a significant contribution to the quality of the plant pulp. In this way, in the example of nature, a vegetable pulp of high quality is produced for subsequent processing (digestion).

The device according to the invention has rotating "teeth" (in the sense of blunt chewing teeth, like the above-mentioned chewing teeth of a cow), the "chewing surfaces" of which interact rhythmically with one another and thereby exert the forces required on the material to be mixed and crushed. Due to the rotation, the "teeth" simultaneously feed the material between the "teeth" and mix the material surrounding the "teeth". An interaction between "teeth" and the vessel wall is not intended.

The device according to the invention has at least two grinding / stirring bodies which rotate in opposite directions about two parallel axes and the surfaces of which form one or more self-contained grinding surfaces which interact in pairs with one another at the narrowing grinding point as a result of the rotational movement. The grinding / stirring bodies are designed, arranged and driven in pairs in such a way that the grinding surfaces of an interacting pair of grinding surfaces for feeding the material to be processed move in the same direction against the corresponding grinding point such that the two grinding surfaces move against one another in front of the grinding point to generate pressing forces. that to generate deformation forces, one of the grinding surfaces in the area of the grinding point is concave and the other is convex, and that to generate the shear forces, the two grinding surfaces move in the same direction but at different speeds in relation to the grinding point.

Various exemplary embodiments of the device according to the invention are to be described in detail with reference to the following figures.

Figur 1

ein Paar von Mahl/Rührkörpern einer bevorzugten Ausführungsform der erfindungsgemässen Vorrichtung in perspektivischer Darstellung;

Figur 2

die beiden Mahl/Rührkörper der Ausführungsform gemäss Figur 1 als Draufsicht parallel zu den Rotationsachsen;

Figur 3

ein Paar von Mahl/Rührelementen der Ausführungsform gemäss Figur 1 als Draufsicht parallel zu den Rotationsachsen;

Figuren 4a bis 4k

das Paar von Mahl/Rührelementen der Figur 3 in verschiedenen Rotationspositionen;

Figuren 5 bis 8

weitere Ausführungsformen der erfindungsgemässen Vorrichtung.

Show:

Figure 1

a pair of grinding / stirring bodies of a preferred embodiment of the inventive device in a perspective view;

Figure 2

the two grinding / stirring body of the embodiment according to Figure 1 as a plan view parallel to the axes of rotation;

Figure 3

a pair of grinding / stirring elements of the embodiment according to Figure 1 as a plan view parallel to the axes of rotation;

Figures 4a to 4k

the pair of grinding / stirring elements of Figure 3 in different rotational positions;

Figures 5 to 8

further embodiments of the device according to the invention.

Figure 1 shows a preferred embodiment of the device according to the invention. The device has two grinding / stirring bodies A and B, which are shown in their corresponding mutual arrangement. The two parallel axes of rotation X and Y with their directions of rotation are also shown. Since the mechanical design of the axes and their connection to a corresponding drive can be designed and implemented by a specialist without difficulty, these parts of the device are not shown.

The relative rotation of the two grinding / stirring bodies A and B, as represented by the two axes X and Y and the two directions of rotation, can also be understood as rotation of the grinding / stirring body B about the axis of rotation X with simultaneous rotation of the body B. the axis of rotation Y and with a stationary body A. The rotation speeds around the axes X and Y should be chosen to be the same regardless of the type of rotation.

The two grinding / stirring bodies A and B each consist of a plurality, for example six, grinding / stirring elements A.1-6 and B.1-6 which all have the same shape. The elements are designed as disks with two parallel main surfaces H and H 'and have a two-fold axis of symmetry that coincides with the axis of rotation (X and Y), that is, each grinding / stirring element is after a rotation of 180 ° about the axis of rotation congruent with itself. The elements A.1-6 and the elements B.1-6 are arranged helically on the axis of rotation X and Y, respectively both screws have the same pitches but opposite turns.

The outer surfaces M connecting the two main surfaces H and H 'of each grinding / stirring element represent the grinding surfaces. Their interaction will be explained with reference to FIGS. 4a to 4k.

Figure 2 shows the two grinding / stirring bodies A and B of Figure 1 as a plan view parallel to the axes of rotation. From this illustration, the grinding point formed by the grinding surfaces MA and MB of the grinding / stirring elements A.1 and B.1 in the current rotational position MS visible. Each additional pair of grinding / stirring elements also forms a grinding point. The width of the grinding point, i.e. the distance between the two grinding surfaces MA and MB at the narrowest point, is given by the dimensions of the grinding / stirring elements and by the distance d between the axes of rotation X and Y. It can also depend on the rotational position of the two elements . Given the grinding elements A.1 and B.1, the width of the grinding point can be varied by adjusting the distance d between the axes of rotation X and Y, means for such an adjustment being known per se and therefore not shown.

The slurry, emulsification or grinding process can be adapted to specific applications by an application-specific adjustment of the distance d. By setting a grinding point width that is in any case larger than the diameter of granular parts of the material to be processed, it is possible to prevent the grinding of such granular parts (eg seeds). By continuously reducing the distance d during the slurry or emulsification process, this can adapt to the changing size of the solid parts during the process be continuously adjusted. This makes it possible that even coarse grains, for example at the beginning of the grinding process (with a relatively wide grinding point or grinding points), are only slightly included in the grinding process, so that the load on the grinder is not caused by jamming large parts between the grinding tools or in the case of Grinding process resulting grinding pockets leads to a standstill.

Figure 3 shows a pair A.1 / B.1 of the grinding / stirring elements of the grinding / stirring body according to Figures 1 and 2. In the figure, arrows also indicate which movements and vortices the stirring effect of the rotating grinding / stirring elements in the surrounding Material created. In addition, the material to be processed is moved against and into the grinding point MS by the two grinding surfaces MA and MB moving from the same side (feed region E) against the grinding point. It can be seen that the movements generated in the material to be processed guarantee, on the one hand, a rhythmic alternation between passing through the grinding point MS (grinding phase) and recovery phase during a movement around the grinding / stirring elements and, on the other hand, are sufficient to ensure continuous homogenization even at relatively low rotational speeds of the material.

The speeds of the grinding surfaces in the grinding point depend on the speed of rotation of the grinding bodies and on the distances from the axes of rotation of the grinding surface points forming the grinding point. These speeds have to be adapted to the sensitivity of the material to be processed. Experiments have shown that the difference in grinding surface speeds at the grinding point in particular is an important machining parameter. Speed differences of the order of 0.3 to 1 m / sec have given very good results for highly sensitive materials.

FIGS. 4a to 4k now show a pair of grinding / stirring elements A.1 and B.1, as already described in connection with FIGS. 1 to 3, in various rotational positions during a full rotation of the two elements to illustrate the grinding process. It can be seen from the figure that a wide variety of grinding situations arise during one revolution of the grinding elements, in other words that for components of the material to be processed not only does a rhythmic alternation between the grinding phase and the recovery phase take place, but also a rhythmic change of the beginning mentioned pressing, crushing, deformation and shearing processes.

• In der Phase a wird die Mahlstelle durch zwei konvexe Mahlflächen gebildet, sodass keine Deformationswirkung entsteht. Die Deformationswirkung nimmt bis zur Phase e zu und nimmt von Phase h an wieder ab.
• In der Phase a haben die beiden Mahlflächen etwa die gleiche Geschwindigkeit, sie üben also keine oder eine sehr kleine Scherwirkung aus. Die Scherwirkung nimmt bis zur Phase e zu und von Phase h an wieder ab.
  Das Maximum an Scherwirkung entsteht bei grösstem Unterschied der Abstände der Mahlstelle von den beiden Rotationsachsen, was bei der vorliegenden Ausführungsform einem Verhältnis von ca. 1:3 entspricht, und womit gute Resultate erzeugt worden sind.
• Zwischen den Phasen a und e wird im Einzugsbereich E der Mahlstelle eine Art Mahltasche kontinuierlich verengt, wodurch Presskräfte entstehen, die die Flüssigkeit langsam aus den festen Teilen des zu bearbeitenden Materials pressen.
• In Phase g erweitert sich die Mahlstelle vorübergehend, sodass sie von dem zu verarbeitenden Material oder von Flüssigkeit allein durchspühlt und so gereinigt wird.

The areas of the grinding surfaces MA and MB forming the grinding point MS vary by their distance from the axis of rotation, which determines their speed, and by their shape (concave or convex), which determines their deformation effect. The following partial grinding processes can be observed at the various stages in FIG. 4:

• In phase a, the grinding point is formed by two convex grinding surfaces so that there is no deformation effect. The deformation effect increases up to phase e and decreases again from phase h.
• In phase a, the two grinding surfaces have approximately the same speed, so they exert little or no shear. The shear effect increases up to phase e and decreases again from phase h.
  The maximum shear effect arises with the greatest difference in the distances between the grinding point and the two axes of rotation, which corresponds to a ratio of approximately 1: 3 in the present embodiment, and which has produced good results.
• Between phases a and e, a type of grinding pocket is continuously narrowed in the intake area E of the grinding point, which creates pressing forces that slowly press the liquid out of the solid parts of the material to be processed.
• In phase g, the grinding point temporarily expands so that it is flushed through by the material to be processed or by liquid alone and thus cleaned.

It can also be seen from FIGS. 4a to 4k that the pair of grinding / stirring elements A.1 / B.1 can rotate in opposite directions but in both directions of rotation. For the axes of rotation X and Y with the directions of rotation indicated in FIG. 4a, the phase sequence in the order a to k applies. The order k to a applies to the reverse directions of rotation (axes of rotation X 'and Y' in FIG. 4k), the same grinding situations being run through in both sequences.

The effect of the screw-like arrangement of the grinding / stirring elements on common axes of rotation, as was described in connection with FIGS. 1 and 2, can also be explained from the sequence of FIGS. 4a to 4k, if this does not appear as a chronological sequence but as relative positions the axis of rotation of adjacent pairs of grinding / stirring elements is considered. It can be seen here that liquid can flow out of the inlet area E, which narrows between phases a to e, in only one direction, namely against the adjacent pair with a still further inlet area. In other words, such a helical arrangement of the grinding / stirring elements produces a further movement of the material to be processed, specifically with a component parallel to the axes of rotation, which additionally has a positive effect on the homogenization of the slurry or emulsion.

Various variations of the embodiment of the device according to the invention shown in FIGS. 1 to 4 are conceivable. For example, the grinding surfaces (M, Fig. 1) obliquely to the main surfaces (H and H ', Fig 1) may be arranged. The grinding / stirring elements can be arranged in any relative position to one another on the axis of rotation instead of in a screw. Arrangements with more than two grinding / stirring bodies are conceivable, these being arranged in pairs with two parallel axes of rotation or in groups of more than two bodies, the associated axes of rotation being parallel and equidistant and each body interacting with more than one other body can stand.

Variations are also conceivable in that the grinding / stirring bodies do not consist of individual grinding / stirring elements, but are in one piece and represent, for example, not a "stepped screw" (FIG. 1) but a continuous screw, the cross section of which, however, is in the form of a grinding at each axial position / Stirring element according to Figure 3. Obviously, the manufacture of such a screw body is significantly more complex.

Further variations are conceivable in that the ratio of the largest to the smallest distance between the grinding surface and the axis of rotation is different than 1: 3 (according to FIGS. 1 to 4). This influences on the one hand the maximum achievable shear effect and on the other hand also the mechanical properties of the grinding / stirring elements. The greater the difference between the two distances, the higher shear effects are achieved, but the narrower the elements become. Good results have been achieved with spacing ratios of 5: 1 to 1.5: 1, in particular 3: 1 to 2: 1.

As a further variation, it is conceivable that the individual grinding / stirring elements are arranged at a distance from one another on the axis of rotation and, for example, their main surfaces do not run or only partially perpendicular to the axis of rotation. The main surfaces may be crooked or curved achieve an increased stirring effect. It is also conceivable that only the elements of the one grinding / stirring body have elements spaced apart from one another with inclined or curved main surfaces, while the other body is configured as shown in FIGS. 1 and 2.

Further exemplary embodiments of pairs of grinding / stirring bodies are shown in FIGS. 5 to 8.

FIG. 5 shows a pair of grinding / stirring bodies, which consists of the same elements as the embodiment according to FIGS. 1 to 4. However, the individual elements of each body are all arranged in the same rotational position on the corresponding axis of rotation. Such a grinding / stirring body can also be produced in one piece relatively easily. The movement of the material to be processed parallel to the axes of rotation described in connection with FIGS. 4a to 4k and produced by the helical arrangement of the grinding / stirring elements is eliminated in this embodiment. However, it can be at least partially compensated for by corresponding oblique or curved main surfaces on the two end faces of the grinding / stirring body.

FIG. 6 shows a further exemplary embodiment of a pair of grinding / stirring elements (section perpendicular to the axes of rotation) or of grinding / stirring elements (top view or section). This is a shape which not only has a two-fold axis of symmetry, like the embodiment according to FIGS. 1 to 5, but also two planes of symmetry S.1 and S.2. Considerations, such as were made in connection with FIGS. 4a to 4k, on such more symmetrical grinding / stirring bodies or elements show that, in the case of the mirror-symmetrical embodiment, the trough-shaped configuration of the feed area is less strong than in an embodiment according to FIGS. 1 to 5, as a result of which the grinding characteristic, in particular its press aspect, is slightly changed. In addition, in a mirror-symmetrical embodiment, the proportion of the grinding surfaces actively involved in the grinding process is reduced, which makes the grinding process somewhat less efficient.

FIG. 7 shows a further exemplary embodiment of a pair of grinding / stirring elements (section perpendicular to the axes of rotation) or grinding / stirring elements (top view or section). It is a kind of gears with cycloid teeth and, for example, five teeth that interlock. The operation of the interacting concave and convex grinding surface areas is the same as described for the other embodiments. Embodiments, as shown in FIG. 7, can also be designed such that they only have an n-fold axis of symmetry (for the embodiment shown in FIG. 7, n = 5) or that they additionally have n planes of symmetry. The difference in effect is the same as already described.

FIG. 8 shows a further exemplary embodiment of a pair of grinding / stirring heads (section perpendicular to the axes of rotation) or grinding / stirring elements (top view or section). In contrast to the previously described embodiments, these are not the same, but differ in the count of their axes of symmetry, which are three or two in the example shown. Accordingly, the two grinding / stirring bodies can only be operated for an interaction at rotation speeds which behave as 3: 2.

Claims (15)

Process for slurrying, emulsifying and / or grinding, the material to be processed consisting of solid parts, solid parts and a liquid, solid parts and several immiscible liquids or consisting of several immiscible liquids being stirred and at least one constricting grinding point (MS) is processed between areas of two self-contained, rotating grinding surfaces (MA, MB), characterized in that for feeding the material to be processed to the grinding point (MS) and for generating pressing forces on the components of the material to be processed two grinding surfaces (MA, MB) are moved from the same side and approaching each other to at least one grinding point (MS), that to generate shear forces on the components of the material to be processed, the two grinding surfaces (MA, MB) at least temporarily at different speeds be moved through the grinding point (MS) un d that in order to generate deforming forces on the components of the material to be processed in the area of the grinding point (MS), at least at times the one grinding surface is concave and the other is convex. A method according to claim 1, characterized in that the generation of the pressing, shearing and deforming forces is subordinate to a temporal rhythm. Method according to one of claims 1 or 2, characterized in that the magnitudes of the forces exerted on the components of the material to be processed are subordinate to a chronological rhythm. Method according to one of claims 1 to 3, characterized in that the distance between the grinding surfaces (MA, MB) at the grinding point (MS) is adjustable during the slurry and / or emulsification process. Device for slurrying and / or emulsifying according to the method according to one of claims 1 to 4 with at least two grinding / stirring bodies (A, B) which can be driven in pairs in rotation about two parallel axes of rotation (X, Y) and their surfaces in pairs form at least one grinding point (MS) interacting, self-contained grinding surfaces (MA, MB), characterized in that the grinding surfaces (MA, MB) are designed and / or can be driven in such a way that they at least at the grinding point (MS) are temporarily movable at different speeds, that the grinding surfaces (MA, MB) have concave and convex areas perpendicular to the axes of rotation (X, Y) and that the grinding / stirring elements (A, B) are arranged relative to each other in such a way that the grinding point ( MS) or grinding points is at least temporarily formed by a concave and a convex grinding surface area. Apparatus according to claim 5, characterized in that the grinding surfaces (MA, MB) are parallel to the axes of rotation (X, Y) of the grinding / stirring body (A, B). Apparatus according to claim 5 or 6, characterized in that the grinding surface or surfaces of each grinding / stirring body (A, B) in planes perpendicular to the axes of rotation (X, Y) points with different distances from the axes of rotation (X, Y) and both concave as well as convex areas. Apparatus according to claim 7, characterized in that the ratio between the maximum distance between the grinding surface and the axis of rotation and the minimum distance between the grinding surface and the axis of rotation is 3: 1 to 2: 1. Apparatus according to claim 7 or 8, characterized in that each grinding / stirring body (A, B) consists of a number of identical grinding / stirring elements (A.1-6, B.1-6) which are arranged on an axis of rotation . Apparatus according to claims 7 to 9, characterized in that the cuts through grinding / stirring elements (A, B) or grinding / stirring elements (A.1-6, B.1-6) perpendicular to the axes of rotation (X, Y) are a n have numerous axes of symmetry, where n is equal to or greater than two, and that they are arranged such that the axis of symmetry coincides with the axis of rotation (X, Y). Apparatus according to claim 10, characterized in that the cuts by grinding / stirring body (A, B) or grinding / stirring elements (A.1-6, B.1-6) perpendicular to the axes of rotation (X, Y) additionally n planes of symmetry ( S.1, S.2). Device according to one of claims 10 or 11, characterized in that equidistant cuts perpendicular to the axes of rotation (A, B) by a grinding / stirring body (A, B) or cuts by the grinding / stirring elements (A.1-6. B. 1-6) of a grinding / stirring body (A, B) are all the same and arranged helically around the axis of rotation (X, Y), the winding direction of the screw of one grinding / stirring body of a pair being opposite to the winding direction of the screw of the other grinding / Stirring body. Device according to one of claims 5 to 12, characterized in that each of the grinding / stirring bodies (A, B) of a pair can be driven in rotation about an axis of rotation (X, Y). Device according to one of claims 5 to 12, characterized in that of a pair of grinding / stirring bodies (A, B) one is stationary and the other can be driven to rotate about one and about itself. Device according to one of claims 5 to 14, characterized in that the distance (d) between the axes of rotation (X, Y) is adjustable.

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