EP1945363B1 - Ball mill having a two-point bearing - Google Patents

Description

The invention relates to a ball mill, in particular a planetary or centrifugal ball mill on a laboratory scale.

In centrifugal ball mills grinding bowls are arranged eccentrically to a drive axis and move on a circular path. The rotation of a grinding bowl around its own axis is prevented in centrifugal ball mills. For this purpose, for example, a built-sprocket, a gear ratio, a toothed belt, a rod guide, a Schmidt coupling or similar device can be used, which prevent the absolute rotation of the grinding bowl.

In contrast, planetary ball mills are based on producing a combined orbital and rotary motion for grinding bowls. As a result of the rotation of the grinding bowls, a centrifugal force directed radially outwards is exerted on the grinding stock. Unlike a centrifugal ball mill, the drive of the grinding bowl in a planetary ball mill causes an absolute rotational movement of the grinding bowl about its own axis, the planetary axis, so that in a planetary ball mill compared to a centrifugal ball mill a significantly larger, further centrifugal component is generated. This is the centrifugal component superimposed, which is generated by the circulation of the grinding bowl to the center axis .. Finally, even the Coriolis force is effective. These three forces result in the planetary ball mill resulting force field to which the grinding balls and the material to be ground are exposed.

With certain dimensions of the rotating parts and certain rotational speeds trajectories for the grinding balls are generated in a planetary ball mill. The grinding balls then move across the grinding bowl until they impinge on the inner wall of the grinding bowl. Thereafter, the grinding balls are taken along the inner circumference of the grinding bowl until the resulting force again ensures that the above-described transverse movement takes place and grinding balls perform a flight movement through the grinding bowl. This is also referred to as a "throwing regime".

The grinding action in a ball mill depends on various parameters, including the impact of the impact of the grinding balls on the material to be ground on the Mahlbecherinnenwand. Further influencing variables are the entire contact surface between the grinding stock and grinding balls or grinding bowl inner wall, the relative movement between the particles to be comminuted and the grinding balls or Mahlbecherinnenwand and the pressure that can be achieved between the mutually contacting surfaces of the ground material and the grinding balls or Mahlbecherinnenwand, as well as the frequency of the stresses of the ground material by contacts with the grinding balls, for example by impact of the balls on the material to be ground.

If the grinding bowls are not self-rotated, a viewer, who assumes the position of the center axis, sees during one revolution of the grinding bowl carrying carrier device about the center axis once the outer jacket of the grinding bowl, while the grinding bowl with the carrier device surrounds the center axis.

If the grinding bowls are not self-rotated, a viewer outside the mill will not perceive any rotation of the grinding bowls. Seen in the laboratory system, that is viewed from outside the mill, the grinding bowl always applies the same area of its outer shell to an observer, while it circles around the center axis with the carrier device.

Performs the grinding bowl in a ball mill through its own rotation, so that the grinding bowl in the laboratory system, that is, in absolute terms, rotates, so an observer in the laboratory system sees the outer shell of the grinding bowl rotates while the grinding bowl with the carrier device surrounds the center axis (planetary ball mill), which consists Possibility to operate the mill in the throwing regime, so that high grinding speeds are achieved at high rotational speeds.

In order to provide a ball mill whose maximum possible speed is not limited by a critical speed at which the ground material or the grinding balls perform no relative movement more to the cup inner wall, planetary ball mills such as those according to the utility model DE 1 836 885 the applicant known. Therein a planetary ball mill is described, which comprises planet carrier, on which grinding jars are fastened with a tensioning device. The planetary carriers are mounted on the fly in a sun disk, which can be driven about a center axis. However, the flying bearing leads at high speeds and thus high centrifugal forces to an enormous bending stress of the shaft of the planet carrier.

Planetary ball mills, in which bearings of the grinding vessels in a bearing insert housing rotatably in a cover plate monitors and which are rotatable this bearing, show the documents JP-A-2002172342 and JP-A-2002172343 ,

Further, in the British document GB 730 494 proposed a ball mill having a single so-called rotary chamber which rotates about its own axis and at the same time revolves around a fixed axis parallel to its own axis, wherein the distance between the two axes is smaller than the radius of the chamber.

Due to the relatively narrowly spaced axes according to GB 730 494 can be achieved that the loading of the inner wall of the chamber more or less lines, however, a high rate of movement both relative to the inner wall surface of the chamber and within the chamber by the relative movement of the components, that is the ground material and the grinding balls. The balls should perform a rolling squeezing movement in relation to the ground material.

The trajectories for the grinding balls characteristic of a planetary ball mill as described above are according to GB 730 494 but not generated.

In the GB 730 494 described mill includes a grinding bowl, which is held in a cage by means of wedges. The wedges are clamped by a spider with the help of screws between the wedge-shaped on his outer wall corresponding grinding bowl and the cage. By the same spider, by which the wedges are tightened to fasten the Mahlbechers in the cage via screws, a lid for closing the Mahlbechers is clamped on the Mahlbecher with another screw.

The cage is mounted in a cylinder which is driven about a fixed axis, the center axis. For storage, an attachment is mounted on the cylinder. The attachment accommodates a roller bearing which engages around the cage projecting upwards beyond the cylinder in the region in which the spider and the actuating screws for fastening the wedges and the cover for the grinding bowl are arranged.

A disadvantage of the known ball mill on the one hand is that due to the small distance of the rotation axis of the grinding vessel to the axis of rotation of the cylinder of the centrifugal force by the rotation about the axis of rotation of the grinding vessel in a comparison at constant speeds only a small additional component by the centrifugal force due to the rotation is superposed on the axis of rotation of the cylinder. By the arrangement according to GB 730 494 should be achieved in accordance with even a squeezing of the ground material in rolling on the Mahlbecherinnenwand grinding balls.

The comminution-friendly desirable choice of parameters for the mill, which summon the total acting on the millbase stress, is not possible with the known ball mill.

Despite this limitation with regard to the mechanical loading of the components, which would be set by the grinding chamber passing through in flight and impinging with great impulse on the Mahlbecherinnenwand grinding balls, the design of the mill is expensive. Thus, the closure of the grinding bowl with its lid by the construction with screws and spider is coupled to the attachment of the grinding bowl in the cage.

In addition, the storage of the cage in the integrally formed cylinder requires a separate structure on the cylinder to accommodate the roller bearing. The production is complicated, since in particular the axial alignment of several items, namely the separate structure for receiving the roller bearing, the cage and the lower journal of the axle extension on the cage must be ensured.

Furthermore, created by the supernatant of the separate structure for receiving the roller bearing, the spider and the screws increased space requirements to secure the grinding vessel in the cage. Another disadvantage is that the spider and projects out of the cross arm part of the screws over the cage, which brings with the rotation of the mill a risk of injury to the operator with it.

It is therefore an object of the invention to provide a ball mill, in particular a planetary or centrifugal ball mill on a laboratory scale, which has a compact design. It is a further object of the invention to provide a ball mill in which the mechanical stress of the ground material is not limited by the construction and the operating parameters can be selected within a wide range.

These objects are achieved by the ball mill according to the invention with the features of the main claim. Advantageous developments are the subject of the associated subclaims.

The invention provides a ball mill, in particular a planetary or centrifugal ball mill on a laboratory scale with a housing, a support device, the is rotatably mounted on the housing about a center axis, at least one receiving device for at least one grinding vessel which is rotatably supported about a receiving axis to the carrier device and is carried by the center axis, a drive for the carrier device, a drive for the receiving device at least one with grinding balls refillable grinding vessel comprising a grinding bowl and a lid for releasably closing the grinding bowl, wherein the grinding bowl is held in the receiving device when inserted into the receiving device, and at least a first and at least a second bearing means for rotatably supporting the at least one receiving device in the support device, wherein the bearing means are arranged at an axial distance from each other, so that the center of gravity of the grinding vessel is located between the bearing devices and the carrier device has a cover plate, in which the one of the storage facilities is sunk.

Basically, it is within the scope of the invention to use arbitrarily shaped grinding media. In addition to the grinding balls mentioned above, in particular also barrel-shaped grinding media or grinding media with a polygonal profile come into consideration. For the description of the invention, the term "grinding balls" is used in the following.

Characterized in that the grinding vessel is held in the receiving device when it is inserted into the receiving device, the holder of the grinding vessel in the receiving device is advantageously independent of closing the grinding bowl with the lid. The grinding vessel is fastened in the receiving device via holding means, which between the Recording device and the grinding vessel, in particular between the receiving device and the grinding cup act. The attachment of the grinding vessel in the receiving device is therefore, so to speak, "on the cup", so that external clamping devices are superfluous.

The arrangement of the storage facilities at an axial distance from each other, so that the center of gravity of the grinding vessel is located between the storage facilities, a high stability of the overall construction can be achieved. In particular, the load can be advantageously kept low by tilting moments relative to the receiving axis. The bending stress relative to the planetary axis is significantly reduced compared to a flying bearing.

In known ball mills, however, the storage takes place at least below the receiving device on journals, which adjoin the region of the receiving device, in which the grinding jar is used. However, the invention allows the storage of the receiving device such that only the area of the receiving device is between the two camps, which receives the grinding vessel. Due to the uniformly large dimensions there are significantly reduced mechanical loads on transitions from large to much smaller diameter as at the transition from a Mahlbecheraufnahme to a journal of the receiving device.

By sinking one of the storage facilities in the cover of the support device a compact design is possible.

Characterized in that the carrier device has a separate cover, the corresponding production of the cover is such that the bearing device can be sunk in the cover, in a simple manner possible, without any handling restrictions by other components of the support device would have to be accepted.

The invention relates in particular to mills on a laboratory scale. This means that the outer dimensions of the support device for the diameter in the range between 10 cm and 2 m and for the height in the range between 4 cm and 1 m move. Volumes for the grinding bowls can be in the range between 5 ml and 2 l, in particular between 12 ml and 1 l, in particular up to 500 ml.

In particular, the mill according to the invention may comprise at least two receiving devices. However, the invention also relates to a mill with a receiving device and a counterweight, as described for example in the patent DE 197 12 905 C2 the applicant is described.

In principle, the mill can have a plurality of receiving devices, in particular arranged at the same angular distance between the individual receiving devices. The receiving devices can be arranged with each other in an even number of receiving devices, for example, diametrically opposite in the carrier device. Three receiving devices can be arranged, for example offset by 120 ° to each other.

According to an advantageous development, the ball mill can at least a third and at least a fourth bearing means for rotatably supporting the carrier device on the housing, wherein the third and the fourth bearing means are arranged at an axial distance from each other, so that the center of gravity of the support device is in an axial position between the storage facilities.

The term "between the storage facilities" is to be understood to mean that the storage facilities have coordinates with respect to the center axis and also the center of gravity has a coordinate with respect to the center axis, wherein the coordinate of the center of gravity with respect to the center axis between the coordinates for the Bearing device is in relation to the center axis.

Characterized in that according to the invention, the receiving device is mounted via a two-point bearing in the support device, wherein the focus of the grinding vessel between the two camps and also the support device itself is mounted with a two-point storage, so that their focus lies between the two camps, the mechanical stress , Especially by occurring tilting moments in the region of the center axis and the receiving axes, advantageously low.

In a further preferred embodiment, one of the bearing means for rotatably supporting the carrier device may be disposed on the housing in a position in the region of one of the bearing means of rotatable bearings of the receiving device in the carrier device and the other of the bearing means for rotatably supporting the carrier device on the housing in a position in Be arranged portion of the other bearing means for rotatably supporting the receiving device in the carrier device.

The bearings for the receiving device and the bearings for the support device are thus so mounted in relation to their coordinates in relation to the center axis substantially at matching positions. This means that the power is absorbed by the upper and lower bearings in each case essentially in one plane. The bearings for the receiving device and the bearing for the support device are therefore arranged in a plane or one above the other, in particular directly above one another. This allows a very stable and compact design.

The storage for the receiving device and the storage for the carrier device can each comprise two bearings. The upper bearing of the receiving device and the upper bearing of the support device are preferably arranged substantially in the same axial position "up" in the support device. Likewise, the lower bearing of the receiving device and the lower bearing of the support device are preferably arranged substantially in the same axial position "down" in the support device.

According to the invention, the distance D12 in the direction of the center axis between the first and second bearing means for rotatably supporting the receiving device in the carrier device substantially coincide with the distance D34 between the third and fourth bearing means for rotatably supporting the carrier device on the housing.

The axial distance D12 between the first and second bearing means for rotatably supporting the receiving device in the carrier device can in Range of 0.04 m to 0.5 m, in particular between 0.07 m and 0.3 m. Also, the axial distance between the third and fourth bearing means for rotatably supporting the carrier device on the housing may be in the range of 0.04 m to 0.5 m, in particular between 0.07 m and 0.3 m.

In order to avoid the fluctuations in the loading of the material to be ground and of the overall apparatus occurring due to the weight force acting only in one direction in a horizontal arrangement of the center axis, the invention further provides that the center axis preferably extends vertically. The receiving axes are preferably arranged vertically.

Advantageously, the upper bearing means for rotatably supporting the receiving device in the carrier device may be arranged such that its upper limit is in a position in the region of the upper edge of the grinding vessel. When the upper bearing device for rotatably supporting the receiving device in the carrier device is sunk in the cover plate of the carrier device and protrudes no further than the upper edge of the grinding vessel out of the carrier device, the overall height of the overall construction with respect to the upper limit is reduced to a minimum.

According to the advantageous compact design, the receiving device is preferably arranged in the carrier device, which is closed at the top by the cover, to be substantially sunk. The grinding jar is positioned over the receiving device in the carrier device. That is, the grinding vessel is preferably arranged in the carrier device substantially sunk.

According to the invention, the total height H of the carrier device with inserted grinding vessel can advantageously be defined substantially by the distance D12 between the first and second bearing means for rotatably supporting the receiving device in the carrier device. The height H of the carrier device, measured from the lower boundary plane of the bottom plate to the upper boundary plane of the cover plate, may in particular assume values in the range from 0.04 m to 0.5 m.

It is further provided that the carrier device has an upper boundary plane for rotating parts of the ball mill, said upper boundary plane is substantially defined by the cover of the support device together with the upper boundary of the grinding vessel.

In this context, the term "boundary plane" is understood to mean a spatial area whose extent in a direction orthogonal to the center axis is substantially greater than its extent in a direction parallel to the center axis.

The support device with the receiving device sunk therein and the grinding vessel also recessed in the carrier device is designed pot-shaped according to the invention. The invention thus provides a ball mill, in which the grinding jars can be arranged in a carrier device such that as a whole a flat, virtually disc-shaped body rotates about the center axis.

A load, in particular relative to the center axis by imbalances is thus almost impossible. Especially at In a planetary ball mill, the load due to dynamic imbalance is particularly critical. The storage according to the invention therefore brings particular advantages in particular for planetary ball mills.

The grinding vessel according to the invention comprises fastening means for releasably securing the lid to the grinding bowl. The receiving device may comprise fastening means, in particular latching means for releasably securing the grinding vessel in the receiving device. The fastening means of the receiving device and the fastening means of the grinding vessel can protrude beyond the upper boundary plane in the ball mill according to the invention. This achieves easy handling of the detachably mounted components of the mill. By gripping the fastening means of the grinding vessel projecting beyond the upper boundary plane, in particular the grinding vessel can be conveniently removed from the receiving device and inserted into it.

The first and the second bearing device for rotatably supporting the receiving device in the carrier device may comprise coaxial bearings. Furthermore, according to the invention, at least one of the bearing devices can comprise a plurality of bearings. In particular, the upper bearing device may comprise a plurality of bearings, in a particularly preferred embodiment at least two bearings arranged on the circumference of the receiving device as viewed from the center axis.

In such an arrangement of two bearings to form the upper bearing means, the receiving device is not spanned along its entire circumference of a bearing, but the bearing size can be advantageously reduced in that several bearings such are arranged so that they each have a common tangent to the outer periphery of the receiving device. For a corresponding arrangement with two bearings on the circumference of the receiving device exists on the relevant field of ball mills the relevant term of the "roller block".

The individual bearings are preferably designed as ball bearings.

The carrier device of the ball mill according to the invention may further comprise a bottom plate. The bottom plate may be formed as a drive pulley for driving the carrier device. Also, the cover may be formed as a drive pulley for driving the support device. The drive can be designed in particular via a belt drive, for example via a drive of the drive pulley via a V-belt, which is set in motion by a motor and kept in motion.

In addition to the possibility of providing the carrier device and the receiving device each with a drive, the invention provides that the drive of the carrier device can be coupled to the drive of the receiving device. For example, a Unterbeziehungsweise translation of a pinion, which is in communication with the carrier device, on a pinion, which is in communication with the receiving device, via a toothed belt drives the receiving device. By replacing the pinion, the lower or gear ratio can be specified, so that in. Reference to the drive of the support device itself a selectable drive for the Receiving device is available without another motor is needed.

The receiving device may comprise an extension which is arranged in an opening of the bottom disk, when the receiving device is arranged in the bottom disk. The extension of the receiving device protrudes through the bottom plate. About the extension, the receiving device may be stored with the first bearing means in the carrier device.

In an advantageous development, it is provided that the bottom plate and / or the cover plate of the carrier device is designed as a flywheel in order to be able to compensate for possible fluctuations in the kinetic energy of the rotation of the receiving device and / or the circulation of the carrier device via its inertia.

Furthermore, one of the bearing devices for rotatably supporting the receiving device in the carrier device and one of the bearing devices for rotatably supporting the carrier device may be arranged on the housing in the region of the bottom plate. In particular, the said storage facilities can be recessed in the bottom plate. Except that the bottom plate essentially assumes the function of the lower end of the support device, it thus serves as a support for said storage facilities, so that advantageously additional components that would allow the attachment of the corresponding storage facilities, can be dispensed with.

In a further preferred embodiment it is provided that one of the bearing means for rotatably supporting the receiving device in the carrier device and one of Storage facilities for rotatably supporting the carrier device are arranged on the housing in the region of the cover. The said storage facilities can be arranged countersunk in the cover. In particular, one of the bearing devices from one direction, the other from the other direction, each seen parallel to the center axis, be sunk in the cover.

For the advantageous arrangement of the bearing devices, the bottom disk and the upper cover disk may comprise openings which correspond to one another and are positioned such that at least one bearing device can be arranged in an opening of the cover disk and at least one bearing device in a corresponding opening of the bottom disk.

According to the invention it is further provided that the bottom plate is rigidly connected to the cover plate. This creates a simple way already a functional backbone for the support device. The support device may also have a jacket element, in particular an annular jacket element. In particular, the jacket element can rigidly connect the bottom plate to the upper cover plate. Thus, an externally closed construction is realized by the carrier device is completed at the top of the upper cover plate, bottom of the bottom plate and outside between the cover plate and the bottom plate on its lateral surface of the jacket element. The entire carrier device thereby obtains a pot-like shape.

Due to the closed construction, the contact of the atmosphere surrounding the carrier device with the interior of the carrier device is at least considerably reduced and thus, for example, the entry of particles into the interior of the Mill prevented, which would increase the susceptibility.

While the cover plate and the bottom discs, as well as the receiving device with regard to the simplest, metal machining, can be made, the sheath element may comprise at least one plastic, so that its contribution to the total weight can be kept vorörhafterhafterweise low. A plastic jacket can be manufactured in particular inexpensively by deep drawing.

The ball mill according to the invention can be operated with a drive power of 0.2 kW to 20 kW. The rotational speed for the rotation of the carrier about the center axis may be as high as 3000 l / min at input speeds ranging from 50 l / min to 100 l / min. Values of up to 6000 l / min. Relative to the carrier device can be selected for the rotational speed of the receiving device during its rotation about the receiving axis.

During the grinding process, heat is generated by the energy input. The inventors have now found that in a Mahlbecheraufnahme according to the invention significantly larger thermal requirements are imposed on the ball mill, which can adversely affect the reliability, the durability of the grinding jars and the grinding result and can not be sufficiently solved with the previous concepts. Also novel Verastungstechniken the grinding jars in the receiving device as in DE 20 2005 015896.8 may under certain circumstances lead to increased friction and thus increased temperature stress.
To provide a ball mill which has improved cooling of the grinding jars consistently gives good grinding results with predetermined grinding parameters, is very comfortable and safe to use, the components have a long life and the operating temperature can be kept within a predetermined range, the ball mill in a preferred embodiment, a cooling device for active cooling of the grinding vessels, said Each grinding station is supplied separately with a cooling medium. The cooling device first guides the cooling medium onto the rotating support device and from there separately to each of the grinding stations. The grinding stations comprise cooling channels which extend at least partially in the receiving device and through which the cooling medium is passed in order to purposefully cool the grinding bowl during the rotation of the carrier device.

Advantageously, this can dissipate the heat produced, inter alia, by the grinding process in the grinding vessel. Possibly. For example, the grinding vessel has a temperature sensor which transmits temperature data to the control device of the ball mill, wherein the cooling can even be regulated by means of these temperature data.

Cooling prevents the jar from overheating, offering advantages in terms of durability and user safety. In addition, the ball mill can be operated at higher speeds due to the improved heat dissipation.

The cooling channels preferably run at least partially within the bottom and / or the annular wall of the receiving cup. Furthermore, there are gaps between the grinding bowl and the receiving cup and the cooling channels within the bottom or the annular wall of the Receiving cup open into these spaces open, so that the cooling medium is passed through the intermediate spaces directly on the outer surface of the grinding bowl, in particular along its annular wall. In other words, the gaps form part of the cooling channels. This ensures effective cooling of the grinding bowl.

In particular, one or more first bores are provided in the bottom of the receiving cup, which open into the intermediate space between the Mahlbecherboden and the bottom of the receiving cup. Further, the space between the grinding bowl and the receiving cup is divided at least into a lower first and an upper second gap, wherein the lower gap is disposed below the Mahlbecherboden and the upper space around the annular wall of the Mahlbechers. Further preferably, the upper intermediate space comprises a first non-circumferential, in particular butterfly-like milled lower portion and a second circumferential upper ring portion. At the support points of the lower portion locking means for locking the grinding bowl are arranged in the receiving cup.

Preferably, the grinding bowl is taken in the upper region slightly below the lid in a hardened ring mount in the receiving cup radially fit. Therefore, bores in the annular wall of the receiving cup extend outside the annular socket to guide the cooling medium therearound. The cooling medium finally flows upwards out of these bores into the atmosphere, ie altogether from bottom to top, at least partially along the grinding bowl outer wall.

The feeding of the cooling medium into the grinding station is preferably accomplished as follows.

The center axis is hollow-drilled and has one or more transverse bores approximately at the level of the cup bottom in order to guide the cooling medium through the hollow axis to the carrier device. Arranged around the center axis, attached to the carrier device, is a distributor plate which for each grinding station has a radially extending connecting channel which connects an annular space about the center axis with the cooling channels of the respective grinding stations.

Thus, the cooling medium is preferably introduced centrally from below into the fixed center axis, flows from there through the transverse bores in the annular space, further through the radial connecting channels in the annular first space below the Mahlbecherboden, from there upwards along the Mahlbecher through the butterfly-like lower portion of the second space, then in the peripheral portion, from there into the bores for bypassing the ring socket and from the upper opening in the Mahlbecherdeckels in the atmosphere. This has proven to be advantageous in practice.

As a cooling medium therefore preferably a compressed gas is used, most easily compressed air. To increase the cooling capacity, it may be useful to mix liquid nitrogen or liquid air into the compressed air or to use liquid nitrogen or liquid air. Since they evaporate immediately at room temperature is still spoken of a gaseous cooling medium.

The invention will now be described by way of example with reference to the accompanying drawings. The same components are identified on the figures with the same reference numerals.

Figur 1

eine schematische Darstellung der erfindungsgemäßen Kugelmühle in einer Seitenansicht,

Figur 2

eine schematische Darstellung der bestückten Trägervorrichtung der erfindungsgemäßen Kugelmühle im Querschnitt,

Figur 3

eine schematische Darstellung einer weiteren Ausführungsform für die Lagerung der Aufnahmevorrichtung,

Figur 4

eine schematische Darstellung der Aufnahmevorrichtung (Figur 4A) und der Aufnahmevorrichtung mit Mahlgefäß (Figur 4B) gemäß einer weiteren Ausführungsform Kugelmühle.

Show it:

FIG. 1

a schematic representation of the ball mill according to the invention in a side view,

FIG. 2

a schematic representation of the assembled carrier device of the ball mill according to the invention in cross section,

FIG. 3

a schematic representation of another embodiment for the storage of the receiving device,

FIG. 4

a schematic representation of the recording device ( FIG. 4A ) and the receiving device with grinding vessel ( FIG. 4B ) according to another embodiment ball mill.

In the representation of the ball mill according to the invention in FIG. 1 is an eruption of a housing 8 to see on which the support device 1 is rotatably mounted about a center axis 15. The ball mill further has a drive 17 for the carrier device. A motor drives a V-belt, which meshes with the bottom disk 6 of the carrier device 1.

Furthermore, the ball mill has a drive 27 for receiving devices 2, via which the receiving devices can be set in rotation around the receiving axes 25. Upon rotation of the carrier device about the center axis 15, a toothed belt via appropriately sized pinion transmits the rotation of the carrier device to the Receiving devices 2, wherein an over- or reduction can take place. In addition, in the context of the invention in principle also the possibility of reversing the direction of rotation.

The carrier device 1 further comprises a cover plate 4 and a jacket element 7. The cover plate is a solid plate which has a thickness of about 3 cm and is made of metal. The heavy round cover fulfills next to the upper end of the support device and the function of a flywheel, which absorbs deviations of each given at a time value for the torque of the average torque, which is determined by integrating the total torque over a circuit, so that the Nonuniformity of the rotational movement remains as low as possible.

The upper boundary plane 10 for rotating parts of the ball mill is essentially defined by the cover 4 together with the upper boundary of the grinding vessel 5.

In the sectional view according to FIG. 2 the housing 8, the mantle element 7 and the motor with the drive for the V-belt are not shown. It can be seen the upper boundary plane 10 for rotating parts of the ball mill, which is essentially defined by the cover 4 together with the upper boundary of the grinding vessel 5. The otherwise massive cover 4 has openings 45, are sunk by the receiving devices 2 in the interior of the support device 1 inside. The grinding vessel 5 is also sunk through the opening 45 in the cover 4 into the interior of the support device 1, wherein the grinding vessel 5 is inserted into the receiving device 2.

Furthermore, in FIG. 2 to see the bottom plate 6. A receiving device 2 is mounted with a first bearing device 31 and a second bearing device 32. rotatably about a receiving axis 25 in the carrier device 1. The upper bearing device 32 is sunk in the massive cover 4.

The first, lower bearing device 31 is arranged in the bottom disk 6. The second, upper bearing device 32 is arranged in an opening 45 in the cover 4. The cover 4 has for this purpose a thickness which is greater than the height of the bearing means 32. The second, upper bearing means 32 is therefore embedded in the cover 4. Coaxially with the opening 45, the bottom disk 6 has an opening 65, in which the first, lower bearing device 31 is arranged. The bottom disk 6 has for this purpose a thickness which is greater than the height of the bearing means 31. The first, lower bearing means 31 is therefore embedded in the bottom disk 6. The vertical distance between the first bearing means 31 and the second bearing means 32 is indicated by D12.

The receiving device 2 is formed in one piece and comprises an upper, a space for receiving the grinding vessel 5 forming region and a lower, an axis extension about the receiving axis forming region. The upper, a space for receiving the grinding vessel 5 forming area is cup-shaped and has an inner contour which is adapted to the outer shape of the grinding vessel 5. This upper, a space for receiving the grinding vessel 5 forming area has a bottom and a at the bottom subsequent annular side wall. The side wall is substantially completely closed. As a result, a substantially full-surface contact of the lateral surface 55 of the grinding vessel 5 with the inner wall of the receiving device 2 is made possible.

The axle extension of the receiving device 2 is hollow in the illustrated embodiment. The axle extension can do this, as in FIG. 2 shown to have a through hole. However, the invention is also to be realized with an axle extension, which includes a blind hole.

An ejector pin 28 for the grinding vessel 5 is held in the hollow axle extension of the receiving device 2. In particular, when an implementation (not shown) of embodiment of the invention is selected without ejector pin 28, the axle extension of the receiving device can be made massive.

The ejector pin 28 is biased upon insertion of the grinding vessel 5 by means of a spring, not shown. For this purpose, the ejector pin 28 has an inwardly to the receiving axis 25 in the direction of the projecting shoulder, which defines an upper seat for the spring. A lower seat for the spring is formed by the lower closure disc, which is connected to the hollow axle extension of the receiving device 2.

When inserting the grinding vessel 5 in the receiving device 2 of the ejector pin 28 is pressed through the bottom of the grinding vessel 5 down, into the hollow axle extension of the receiving device 2. In this position, the grinding vessel 5 is secured in the receiving device 2 by latching. The spring is compressed. If the attachment of the grinding vessel 5 in the Detached receiving device 2, the spring relaxes and pushes the ejector pin 28 upwards so that it moves the grinding vessel 5 with upward.

The carrier device itself is rotatably mounted about the center axis 15 via a third bearing device 33 and a fourth bearing device 34. The third bearing device 33 is arranged in the bottom disk 6. The thickness of the bottom disk 6 is greater than the height of the bearing device 33. The third bearing device 33 is therefore embedded in the bottom plate 6 together with the first bearing device 31.

The fourth bearing device 34 is arranged via a retaining flange in the region of the cover disk 4. The fourth bearing means 34 may also be arranged in the cover 4, without a retaining flange is provided. The mill according to the invention can therefore also be designed such that the fourth bearing means 34 is embedded together with the second bearing means 32 in the cover plate 4.

The vertical distance between the third bearing means and the fourth bearing means 33 and 34 is indicated by D34. The distance D34 substantially coincides with the distance D12 between the first bearing device 31 and the second bearing device 32.

FIG. 3 shows a schematic representation of the area around the receiving device 2 according to an arrangement according to another embodiment. The receiving device 2 is arranged rotationally symmetrical to the receiving axis 25. The receiving device 2 is mounted in a first storage device 31. The storage device 31 comprises a coaxial with the receiving device 2 arranged around the receiving axis 25 bearing.

The second bearing device 32 comprises two bearings 325 and 322, which support the receiving device 2 at its periphery. In the example shown, the bearings 322 and 325 are ball bearings with a significantly smaller diameter than the receiving device 2. The bearings 322 and 325 and the receiving device 2 are not arranged coaxially with one another. However, each of the bearings 322 and 325 has a common tangent to the receiving device 2. The two bearings 322 and 325 are arranged on the side facing away from the center axis 15 side of the receiving device 2 in order to accommodate the higher because of the centrifugal forces there can.

In the FIG. 3 schematically shown embodiment of the invention is not limited to the use of two bearings, but it can also be arranged less or more bearings on the circumference of the receiving device.

The recessed arrangement of the grinding vessel in the receiving device, which is made possible by the bearing arrangement according to the invention, creates by the compact design the conditions for operating the ball mill with very high speeds. Thus, compared to conventional ball mills increased demands on the strength of the grinding vessel and receiving device are connected. Depending on the choice of materials, there may be an increased abrasion at the contact points between the grinding vessel and receiving device.

To prevent these cases is in a further embodiment of the ball mill according to the invention provided that the receiving device has an additional socket for the grinding vessel. In FIG. 4 is a schematic representation of such a recording device shown with socket, wherein in FIG. 4A the cradle alone and in FIG. 4B the receiving device is shown with inserted grinding vessel.

The receiving device 2 is held between the upper bearing 32 and the lower bearing 31. It has as a version for the grinding vessel in the embodiment shown, a ring member 26 which is attached to the inner side wall of the receiving device 2. Furthermore, the receiving device 2 comprises a bottom element 261 as a further component acting as a socket. The bottom element 261 simultaneously acts as a centering device for the central positioning of the grinding vessel in the ring element 26.

In FIG. 4B is the in FIG. 4A shown receiving device 2 shown with inserted grinding vessel 5. The side wall 55 of the grinding vessel 5 abuts the holder 26, so that the grinding vessel 5 is held radially substantially by the socket 26 in the receiving device 2. At its bottom side, the grinding vessel 5 also on holding means. These are designed as a ring element 561, which surround the bottom element 261 of the receiving device 2.

In order to protect grinding jar and receiving device particularly efficiently against abrasion during operation of the ball mill, the holding means 26 and 261 are preferably hardened. According to another suitable embodiment, the ring element 26 and / or the bottom element 261 is hard-coated.

It will be apparent to those skilled in the art that the invention is not limited to the embodiments described above, but rather can be varied in many ways. In particular, the features of the individual embodiments can also be combined with each other.

LIST OF REFERENCE NUMBERS

1

support device

15

central axis

17

Drive for carrier device

2

cradle

25

Pin adapter

26

Holder for the grinding vessel, ring element

261

Holder for the grinding vessel, bottom element, centering element

27

Drive for cradle

28

ejector pin

31, 32, 33, 34

Storage facility

4

cover plate

45

opening

5

grinding vessel

55

Lateral surface of the grinding vessel

561

Holding means, ring element

6

bottom disk

65

opening

7

jacket element

70

Fastening means, lever element

8th

casing

10

upper limit plane for rotating parts

Claims (25)

1. A laboratory scale planetary or centrifugal force ball mill, comprising:

   a housing;

   a support means (1) which is mounted on the housing for rotation around a central axis (15);

   at least one receptacle means (2) for at least one grinding jar (5), which is mounted for rotation around a receptacle axis (25) relative to said support means (1) and is entrained thereby around said central axis (15);

   a drive (17) for said support means;

   a drive (27) for said receptacle means;

   at least one grinding jar (5) adapted to be filled with grinding balls, comprising a grinding bowl and a lid for releasably closing said grinding bowl, wherein the grinding jar is retained in the receptacle means (2) when inserted in the receptacle means; and comprising

   first and second bearing means (31, 32) for rotatably mounting the receptacle means (2) in the support means (1); wherein

   the bearing means (31, 32) are axially spaced from each other such that the center of gravity of the grinding jar (5) lies between the bearing means (31, 32); and

   the support means (1) has a cover plate (4) with one of the bearing means (31, 32) arranged recessed therein.
2. The ball mill according to claim 1, characterized in that

   the ball mill comprises third and fourth bearing means (33, 34) for rotatably mounting the support means (1) on the housing;

   wherein the third and fourth bearing means (33, 34) are axially spaced from each other such that the center of gravity of the support means (1) lies between said bearing means (33, 34).
3. The ball mill according to claim 2, characterized in that

   one of the bearing means (33, 34) for rotatably mounting the support means (1) on the housing is arranged at an axial position in the region of one of the bearing means (31, 32) for rotatably mounting the receptacle means (2) in the support means (1); and

   the other one of the bearing means (34, 33) for rotatably mounting the support means (1) on the housing is arranged at an axial position in the region of the other bearing means (32, 31) for rotatably mounting the receptacle means (2) in the support means (1).
4. The ball mill according to any of the preceding claims, characterized in that

   the axial distance (D12) between the first and second bearing means (31, 32) for rotatably mounting the receptacle means (2) in the support means (1)

   is substantially the same as the axial distance (D34) between the third and fourth bearing means (33, 34) for rotatably mounting the support means (1) on the housing.
5. The ball mill according to claim 1, characterized in that

   the central axis (15) extends vertically.
6. The ball mill according to any of the preceding claims, characterized in that

   the upper bearing means (32) for rotatably mounting the receptacle means (2) in the support means (1) is arranged so that its upper boundary lies at an axial position in the region of the position of the upper edge of the grinding jar (5).
7. The ball mill according to any of the preceding claims, characterized in that

   the receptacle means (2) is arranged in the support means (1) substantially recessed therein.
8. The ball mill according to any of the preceding claims, characterized in that

   the grinding jar (5) is arranged in the support means (1) substantially recessed therein.
9. The ball mill according to any of the preceding claims, characterized in that

   the total height (H) of the support means (1) with grinding jar (5) inserted

   is substantially defined by the distance (D12) between the first and second bearing means (31, 32) for rotatably mounting the receptacle means (2) in the support means (1).
10. The ball mill according to any of the preceding claims, characterized in that

    the support means (1) has an upper boundary plane (10) for rotating parts of the ball mill;

    wherein said upper boundary plane (10) is substantially defined by the cover plate (4) of the support means (1) along with the upper boundary of the grinding jar (5).
11. The ball mill according to any of the preceding claims, characterized in that

    the grinding jar comprises fastening means for releasably securing the lid to the grinding bowl; and

    the receptacle means has fastening means for releasably securing the grinding jar in the receptacle means;

    wherein the fastening means of the receptacle means and the fastening means of the grinding jar protrude beyond the upper boundary plane.
12. The ball mill according to any of the preceding claims, characterized in that
    the first and second bearing means (31, 32) comprise mutually coaxial bearings.
13. The ball mill according to any of the preceding claims, characterized in that
    at least one of the bearing means (31, 32, 33, 34) comprises a plurality of bearings.
14. The ball mill according to any of the preceding claims, characterized in that
    the upper bearing means (32) for rotatably mounting the receptacle means (2) in the support means (1) comprises a plurality of bearings.
15. The ball mill according to any of the preceding claims, characterized in that
    at least one of the bearing means (31, 32, 33, 34) comprises at least one ball bearing.
16. The ball mill according to any of the preceding claims, characterized in that
    the support means (1) comprises a bottom plate (6) in parallel to the cover plate (4).
17. The ball mill according to any of the preceding claims, characterized in that
    the bottom plate (6) is configured as a drive pulley.
18. The ball mill according to any of the preceding claims, characterized in that
    the bottom plate (6) and/or the cover plate (4) is/are configured as a flywheel.
19. The ball mill according to any of the preceding claims, characterized in that
    one of the bearing means (31, 32) for rotatably mounting the receptacle means (2) in the support means (1) and
    one of the bearing means (33, 34) for rotatably mounting the support means (1) on the housing
    are arranged in the region of the bottom plate (6).
20. The ball mill according to any of the preceding claims, characterized in that

    one of the bearing means (31, 32) for rotatably mounting the receptacle means (2) in the support means (1) and

    one of the bearing means (33, 34) for rotatably mounting the support means (1) on the housing

    are arranged in the region of the cover plate (4).
21. The ball mill according to any of the preceding claims, characterized in that

    the bottom plate (6) and the upper cover plate (4) have mutually corresponding openings (65, 45)

    which are positioned such that at least one bearing means can be arranged in an opening (45) of the cover plate (4) and at least one bearing means can be arranged in an opening (65) of the bottom plate (6).
22. The ball mill according to any of the preceding claims, characterized in that
    the bottom plate (6) is rigidly connected to the cover plate (4).
23. The ball mill according to any of the preceding claims, characterized in that
    the support means (1) comprises a casing element (7).
24. The ball mill according to any of the preceding claims, characterized in that
    the casing element (7) rigidly connects the bottom plate (6) to the upper cover plate (4).
25. The ball mill according to any of the preceding claims, characterized in that
    the ball mill comprises cooling means which direct a cooling medium to the support means rotating during operation and to the at least one grinding station in order to dissipate the heat generated by the grinding operation from the grinding jars.

Images