WO2006111381A2

WO2006111381A2 - Stirring mill

Info

Publication number: WO2006111381A2
Application number: PCT/EP2006/003618
Authority: WO
Inventors: Roland Reichardt; Wolfgang Wiechert
Original assignee: Universität Siegen
Priority date: 2005-04-20
Filing date: 2006-04-20
Publication date: 2006-10-26
Also published as: DE102005018399A1; WO2006111381A3

Abstract

The invention relates to a grinding device which is provided with a grinding container comprising at least one crushing gear which consists of at least one rotor which is fixed to a motor-driven shaft and is used for accelerating a plurality of grinding bodies placed in the grinding container (2), wherein said grinding device is characterised in that the grinding container comprises at least two crushing gears (3,7,10,11; 4,8,9) whose shafts are arranged in a parallel position to each other. Said invention also relates to a grinding device provided with a grinding container comprising at least one crushing gears consisting of at least one rotor which is fixed to a motor-driven shaft and is used for accelerating a plurality of grinding bodies placed in the grinding container, wherein said grinding device is characterised in that at least one rotor (10, 11) or a rotor blade (10, 11) of at least one shaft (3) is embodied in such a way that in case of collision of the rotor and the rotor blade with grinding bodies (13,14), said grinding bodies (13,14) follow the direction of movement whose predominant direction, in particular the greatest speed component is placed in the longitudinal direction of the shaft (15). The invention also relates to a grinding device provided with a grinding container comprising at least one crushing gears consisting of at least one rotor which is fixed to a motor-driven shaft and is used for accelerating a plurality of grinding bodies placed in the grinding container characterised in that the rotor (10, 11) is embodied in the form of an component mountable on the shaft (3, 4) or inserted therethrough and fixed. A rotor to be used in the grinding device is also disclosed.

Description

grinder

The invention relates to a grinding apparatus comprising a grinding container, which comprises at least one grinder with at least one rotor mounted on a shaft driven by a motor for accelerating a plurality of grinding bodies provided in the grinding container.

Such grinding devices are known in the art, often used as grinding media balls. In many cases, such a grinding device is used to further reduce an already powdered material in its grain size, the grinding process essentially based on the fact that in the grinding container accelerated by the rotor grinding media such as the aforementioned balls collide with each other in many cases and thereby arranged between these grinding media materials pound. It can be produced in this way grain sizes down to the nanometer range. Such devices are not only suitable for further grinding of powders, but in principle the use in liquids, e.g. Suspensions, be possible. In that regard, the pumps are suitable both for dry grinding and wet grinding.

In order to accelerate the grinding bodies provided in the grinding container to high speeds, it is essentially provided to arrange one or more rotors, which rotate in the grinding container at high speed, on one or more shafts, which may each be motor-driven. Often 8 to 20 meters / second peripheral speed is reached, preferably the speed is greater than 10 meters / second. In this case, the rotors extend from the drive shaft to the vicinity of the container wall, wherein a gap between the rotor tip and container wall remains.

Due to the large number of grinding media in a grinding container, therefore, a grinding body will repeatedly collide with a rotor or a rotor blade or blade of such a rotor and be accelerated by this collision. The thus accelerated grinding bodies repeatedly collide against each other or even to the wall of the grinding container, so that the ground material is crushed.

The grinders known in the prior art essentially have grinding containers which, at least perpendicular to the longitudinal axis of the grinding container, which is often preferably parallel to a shaft, have a circular cross-section. Accordingly, grinding container are substantially cylindrical, frusto-conical or spherical, since all of these forms above are structurally particularly easy to manufacture.

In the known grinding devices in which e.g. the container volume in a vertical arrangement up to 80% and in a horizontal arrangement up to 40% with grinding media, such as. Kugein can be filled, there is the problem that the collision of the grinding media with a rotor essentially accelerates the grinding media outwards towards the container wall, where they slow down due to impact processes and then in a collection of a variety of Move Mahlkörpern inside along the container wall, in particular roll along with balls.

Thus, in the wall region of a grinding container, there are grinding media accumulations in which the individual grinding media have only a very small velocity component with respect to one another and the total accumulation of grinding media is essentially undisturbed on the grinding media Container wall moved along. By the rotation of the rotor, the Mahlkörperansammlung receives a direction of movement that corresponds to that of the rotor.

Due to this movement, centrifugal forces continue to arise, which cause the grinding bodies to always be accelerated in the direction of the grinding container wall due to their movement, so that there is only a slight probability, especially at high speeds, that a grinding body moving in the region of a container wall will make its way back to the container Rotor passes, again collided with the rotor and is accelerated again.

In practice, it has been observed that all of the grinding media of such a generic grinding apparatus are highly likely to be in the region of the inner wall of the grinding container and the grinding media density in the center of the grinding apparatus, in which at least one shaft is arranged with at least one rotor, or at least the environment of a rotor is very low.

The object of the invention is to provide a grinding device and usable therein rotors, by means of which the grinding efficiency can be significantly increased, especially at the same rotor speed.

This object is achieved according to a first aspect of the invention in that a grinding container comprises at least two grinders whose waves are arranged parallel to each other.

The typically adjusting orbital motion of a plurality of grinding bodies essentially around the central axis of the driven shaft can already be avoided or at least reduced by the fact that the juxtaposition of two shafts of the grinding mechanisms means that no discrete center of motion can be set. The juxtaposition of the waves of these grinders thus provides for a disturbance in the overall system, which leads to a higher probability of being on the inside a grinding device along moving grinding body are deflected in the direction of the interior of the grinding device and thus given a higher probability of new collisions between grinding media and rotor blade or rotor blades.

In a further preferred embodiment, it can be provided that a shaft has a plurality of rotors spaced apart from each other, wherein the rotors of at least two adjacent shafts are interlaced, which may in particular mean that a rotor of a shaft at least partially in a region between two rotors another wave is arranged. In particular, by the meshing can again be achieved that collision probabilities between grinding media and rotors increase and in particular the free path lengths of a grinding body between two rotor collisions are reduced. Thus, a grinding media, in particular e.g. a ball, on its way through the grinding container due to the increased probability of multiple collisions absorb increased kinetic energy.

Alternatively or in combination with the aforementioned embodiment, it can be provided that two shafts arranged next to one another have different directions of rotation in the grinding operation. This, in particular, when the rotors are further entangled in each other, further leads to a disruption of the known in the prior art uniform circular motion of a plurality of grinding media around a common center, such as the shaft axis, since a usually uniform, forming around the shaft axis Circular movement of a plurality of grinding media in one direction of rotation is substantially disturbed by the fact that a rotating shaft in the opposite direction is provided with rotors. Accordingly, in such a preferred embodiment, no preferred rotational movement of a plurality of grinding bodies can be established in only one direction. Again, this creates a significant disturbance in the smooth motion, so here too the likelihood is increased by this Execution of the grinding media in the inner region of the grinding container with the rotors arranged there deflect.

The different directions of rotation of the shafts arranged next to one another can be achieved, for example, by driving these shafts through different motors or else by having one shaft from the other, e.g. is driven via a transmission connection, for example by gears or belts.

According to a further aspect of the invention, the object can be achieved alternatively or in addition to the previous embodiments, that at least one rotor or a rotor blade of a rotor of at least one shaft is formed such that in collisions between a rotor or rotor blades and grinding bodies this Grinding received a direction of movement, which has a component in the wavelength direction, in particular a preferred direction in the wavelength direction, in particular their largest speed component is in this direction.

As mentioned above, it is a problem with such grinding devices and in particular agitator ball mills that the plurality of grinding media due to the excellent circular motion of the rotors around the shaft axis and the associated centrifugal force concentrate in the region of the inner wall of the grinding container and little or no get a further acceleration through the rotors.

The rotors, as known in the art, are often cut from plates and have surfaces perpendicular to the direction of rotation which may collide with the grinding media. Due to this fact, in a collision with such rotors, which have their maximum velocity perpendicular to the radial direction, grinding media mainly receive an impulse which is oriented in the direction of the container wall surrounding a rotor, so that the grinding bodies inevitably move inwards accumulate this direction and thus concentrate in a known manner to the container wall and circulate there in a circle.

An essential core idea in the embodiment according to the invention is that according to the invention in a collision between a grinding body and a rotor or a rotor blade of such a rotor, the grinding body is given a preferred direction in the direction of the wavelength axis. This avoids that the grinding media concentrate on the inner wall area by a simple collision, in particular it can be achieved by an arrangement of several rotors on an axis or in connection with the previous embodiments with a rotation of the rotors with each other, a grinding body by collision is accelerated with a rotor in the direction of an axially adjacent another rotor. Thus, the inventive design significantly increases the probability that a grinding body, in particular a ball, is subject to multiple collisions with rotors on the way inside a grinding container, as a result of which higher speeds, in particular relative speeds of the grinding bodies, can be achieved with one another.

The achievement of a preferred direction due to a collision between a grinding body and a rotor or rotor blades can particularly preferably be achieved in that a rotor blade has a baffle which is arranged obliquely to the rotational direction of the rotor blade, in particular by an angle of 5 to 85 degrees, especially preferably 45 degrees.

Accordingly, a rotor blade can be designed similar to an aircraft or helicopter blade in order to achieve a deflection of the grinding bodies colliding with the rotors in the axial direction of the driving shaft. An impact surface of such a rotor blade may also have a curved surface in addition to the planar or planar design. In particular, it can be provided that a rotor blade has an elliptical cross-section. It is essential here that the long axis of such an elliptical cross-sectional shape oblique to the Direction of rotation of the rotor blade is arranged to give it in a collision with a grinding body this the desired preferred direction.

Preferably, the embodiment is chosen such that the longitudinal axis of a rotor blade itself is arranged substantially perpendicular to the shaft longitudinal axis and thus a baffle also obliquely to this shaft longitudinal axis.

Based on the both planar and curved surfaces of the baffles of rotor blades, it can therefore be provided that a rotor blade is designed as a flat profile, in particular with a rectangular or elliptical cross section.

The formation of rotor blades according to the previous comments can be used both alone in conventional grinding devices as well as in connection with the aforementioned other possible embodiments of the arrangement of adjacent shafts and possibly entangled in the same direction or in opposite directions rotors.

Accordingly, it can be provided in a particularly preferred embodiment that the baffles of two successive in the longitudinal direction of the rotor blades, in particular rotors of adjacent shafts and particularly preferably of interlocked rotors are assigned to each other or tilted towards each other.

By means of this particularly preferred embodiment, it can be achieved that, in the event of a collision of grinding bodies with adjacent rotors, these grinding bodies are accelerated toward one another, as a result of which these grinding bodies receive a very high relative speed to one another. As a result of the collisions, the adjacent rotors shoot each other towards the grinding media. In order to achieve a particularly high variability and serviceability of the known grinding devices, it is also possible in an alternative or cumulative aspect of the invention that a rotor is designed as a component which can be screwed on and fastened onto a shaft or fastened by the shaft. As a result, it is achieved, in particular in conjunction with the abovementioned features according to the invention, that the rotors can be fastened in a different arrangement on a drive shaft. Thus, for example, rotors with obliquely arranged baffles can be fastened to the shaft in such a way that their baffles are assigned to one another and the rotors thus mutually shoot the grinding bodies, in particular the balls, during operation. Also, areas may be provided on a shaft in which the rotors always carry the grinding media in one direction only.

In this case, it is preferably provided that in a plug connection between the shaft and rotor a safeguard against rotation of these components is provided with each other. For example, this can be achieved in that the shaft is designed as a polygonal shaft, for example triangular shaft, square shaft, particularly preferably hexagonal shaft, wherein the rotors pushed onto this shaft have a cross section arranged in the rotor center of corresponding cross section, so that a rotor by means of this opening the shaft can be plugged on.

In particular, in the case of a plurality of rotors, which can be attached one after the other to such a shaft, it can be provided that the rotors are position-limiting with respect to one another, which means that the position of a rotor is secured by the position of adjacent rotors. In this case, it may in particular be provided that a plurality of rotors are clamped between a stop provided on the shaft in the region of the one shaft end and a fastening element in the region of the opposite shaft end. The above-mentioned embodiment has the particular advantage that optionally rotors of different types can be combined in accordance with the abovementioned aspects of the invention. Likewise, it can be easily replaced by wearing worn rotors.

Exemplary embodiments of the invention are shown in the following figures. Show it:

1 shows a grinding device of the type according to the invention with two side by side parallel grinders, which are each driven by a separate motor

Figure 2 shows an arrangement in which a grinder is driven via a transmission connection to a motor-driven grinder

Figure 3 shows an embodiment of the invention, in which the rotors are equipped with obliquely arranged to the wavelength direction baffles

4 shows an illustration of the acceleration principle due to the obliquely set baffles

1 shows a grinding device 1 according to the invention, which has a grinding container 2, in which two grinders are arranged side by side, whose respective shafts 3 and 4 are arranged parallel to each other. It can be seen here that the two shafts are driven by different motors, namely the shaft 3 by the motor 5 and the shaft 4 by the motor 6. Both shafts are preferably operated such that their direction of rotation is opposite.

In addition, it can be seen here that in this preferred embodiment, the rotors 7 of the grinder of the shaft 3 and the rotors 8 of the grinder of the shaft 4 are arranged mutually entangled, which means that a rotor, eg the rotor 9 of the shaft 4, between the rotors 10 and 11 of the shaft 3 is arranged.

As mentioned at the outset, it can be significantly prevented by these parallel juxtaposition of the grinders that results in a plurality of balls or generally grinding bodies which rotate on a circular path around a common center in the grinding container 2. Due to the design with two parallel shafts, there is no excellent center point within such a grinding container designed to permit such movement.

FIG. 2 shows a further embodiment in which one of the motors, in this case the motor 6, has come to be dispensed with. The drive of the arranged in the representation 2 below shaft 4 is effected by a transmission connection, here for example by means of a belt or a chain 12, to connect the two shafts. As a result, with an appropriate design of the transmission connection, it can also be achieved automatically that the shaft 4 rotates in the opposite direction of rotation as the shaft 3.

3 shows the aspect according to the invention, that in a grinding device 1, comprising a grinding container 2 and a grinder arranged therein with a shaft 3 and arranged therein rotors 7, wherein the rotors 7 baffles F, on the one hand the direction of rotation and on the other hand Shaft 3 are formed obliquely.

The embodiment according to FIG. 3 is shown here only with a grinder, but it is also possible to combine this embodiment according to the invention with the embodiments according to FIGS. 1 and 2.

Here, it can essentially be seen that the baffles F of two juxtaposed rotors 10 and 11 are designed such that these surfaces are assigned to each other due to their tilting. If one looks at the principle of operation, in particular with reference to FIG. 4, it becomes here it can be seen that two grinding bodies 13 and 14, which are accelerated by these adjacent rotors 10 and 11 by collision, are accelerated towards one another, ie these two grinding bodies have a very high relative speed to each other, so that in the event of a collision of these bodies there are particles to be mated between them can be crushed very effectively.

FIG. 4 essentially clarifies the functional principle. Shown is the top view of a rotor 10 according to the invention from above on its end face, so that its cross-section is visible in the present case. The cross section is here approximately elliptical, with the long axis of the ellipse being arranged obliquely, preferably at an angle of 10 to 45 degrees, to the direction of rotation. The direction of rotation is illustrated here by the arrow R. If, in the area of the rotation trajectory of the rotor, a grinding element 13 is located or if such moves toward the rotor 10, then the grinding element 13 is accelerated in the direction of the arrow 15 due to the collision. The grinding body thus receives a component of movement which lies in the direction of the shaft axis, wherein the shaft axis is aligned here parallel to the direction of the arrow 15.

In this way, it becomes apparent that with an acceleration of grinding bodies due to collisions with rotors and the concomitant preferential direction parallel to the shaft, trajectories of grinding bodies which can directly counter each other result. Accordingly, the probability is significantly increased that accelerated by collision with rotors grinding bodies collide directly frontally or only at low angles to each other, so that their kinetic energy can be maximally implemented in a comminution of intervening particles.

Claims

claims

1. Grinding device comprising a grinding container which has at least one grinder with at least one rotor mounted on a shaft driven by a motor for accelerating a plurality of provided in the grinding container grinding bodies, characterized in that a grinding container (2) at least two grinders (3, 7,10,11 and 4,8,9), whose shafts (3,4) are arranged parallel to each other.

2. Grinding device according to claim 1, characterized in that at least one shaft (3,4) has at least two rotors spaced from each other in the longitudinal direction rotors (10,11).

3. Grinding device according to claim 2, characterized in that the rotors (9,10,11) of at least two adjacent shafts (3,4) are arranged interlaced, in particular such that a rotor (9) of a shaft (4) in a region between two rotors (10,11) of another shaft (3) is arranged.

4. Grinding device according to one of the preceding claims, characterized in that two juxtaposed shafts (3,4) have different rotational direction in the grinding operation.

5. Grinding device according to claim 4, characterized in that the shafts (3,4) by different motors (5) or a shaft (4) from the other (3) via a transmission connection (12) is driven.

6. grinding device comprising a grinding container, which comprises at least one grinder with at least one rotor mounted on a shaft driven by a motor for accelerating a plurality of provided in the grinding container grinding media, in particular according to one of previous claims, characterized in that at least one rotor (10,11) or a rotor blade of a rotor (10,11) of at least one shaft (3) is formed such that in collisions between a rotor / - wings and grinding bodies (13 , 14) these grinding bodies (13, 14) receive a direction of movement whose preferred direction, in particular their largest speed component, lies in the longitudinal direction (15) of the shaft.

7. Grinding device according to claim 6, characterized in that a rotor blade has a baffle surface (F), which is arranged obliquely to the direction of rotation ® of the rotor blade (10).

8. Grinding device according to one of the preceding claims 6 or 7, characterized in that the longitudinal axis of a rotor blade (10) is arranged substantially perpendicular to the longitudinal axis of the wave (15) and a baffle surface (F) obliquely to the shaft longitudinal axis (15).

9. Grinding device according to one of the preceding claims 6 to 8, characterized in that a baffle surface (F) has a curved surface.

10. Grinding device according to one of the preceding claims 6 or 7, characterized in that a rotor blade (10) is designed as a flat profile, in particular with a rectangular or elliptical cross section.

11. Grinding device according to one of the preceding claims 6 or 7, characterized in that the baffles (F) of two successive in the longitudinal direction of the rotor blades (10,11), in particular of rotors juxtaposed waves assign each other, or are tilted towards each other.

12. Grinding device comprising a grinding container, which has at least one grinder with at least one rotor mounted on a shaft driven by a motor rotor for accelerating a plurality of provided in the grinding container grinding media, in particular according to one of the preceding claims, characterized in that a rotor (10 , 11) as on a shaft (3,4) or on the shaft (3,4) durchsteckbares and fastened component is formed.

13. Grinding device according to claim 12, characterized in that in the plug connection between the shaft (3,4) and rotor (10,11) is provided a backup against rotation of the components with each other.

14. Grinding device according to one of the preceding claims 12 or 13, characterized in that a plurality of rotors one after the other are attachable to a shaft, in particular, wherein the rotors are position-limiting one another.

15. Grinding device according to one of the preceding claims 12 to 14, characterized in that a plurality of rotors are clamped between a stop provided on the shaft and a fastening element.

16 rotor for use in a grinding device, in particular according to one of the preceding claims, characterized in that a rotor (10,11) or a rotor blade of a rotor (10,11) is formed such that in collisions between a rotor / wings (10,11) and grinding bodies (13,14) of a grinding device these grinding bodies (13,14) receive a direction of movement, the preferred direction, in particular their largest speed component, in the longitudinal direction (15) of the shaft (3), on which the rotor (10,11) is fastened.