EP2063992B1 - Vibration mill and method for the operation of a vibration mill - Google Patents

Vibration mill and method for the operation of a vibration mill Download PDF

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Publication number
EP2063992B1
EP2063992B1 EP07803119.2A EP07803119A EP2063992B1 EP 2063992 B1 EP2063992 B1 EP 2063992B1 EP 07803119 A EP07803119 A EP 07803119A EP 2063992 B1 EP2063992 B1 EP 2063992B1
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EP
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Prior art keywords
rotational speed
drive
speed
vibration mill
grinding
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EP07803119.2A
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German (de)
French (fr)
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EP2063992A1 (en
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Ralf STROHHÄUSL
Darius Rieger
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FLSmidth AS
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FLSmidth AS
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C17/00—Disintegrating by tumbling mills, i.e. mills having a container charged with the material to be disintegrated with or without special disintegrating members such as pebbles or balls
    • B02C17/14—Mills in which the charge to be ground is turned over by movements of the container other than by rotating, e.g. by swinging, vibrating, tilting

Definitions

  • the present invention relates to a vibrating mill, preferably a disc vibrating mill, comprising a grinding unit and a vibrating drive, by means of which the grinding unit can be excited to vibrations dependent on the driving speed of the vibrating drive.
  • Such vibratory mills are used in particular for grinding a sample of free-flowing, granular ground material in the course of preparing the sample for desired analyzes, for example for X-ray-based investigations of the elements contained with suitable equipment (eg XRF).
  • suitable equipment eg XRF
  • Such a vibratory mill is from the US5733173 known.
  • regrind which is rinsed by a liquid in the grinding chamber, is conceivable.
  • the sample which may be, for example, a rock sample, ore, slag, etc., is mixed and ground in the vibratory mill with excipients and then pressed with auxiliaries to a tablet which is fed to an analyzer for analysis of the ingredients.
  • the sample must be crushed in such a way that all components give a homogeneous mixture, for which a fine and uniform comminution of the material to be ground in the vibratory mill is essential. Often it is required that after the grinding process, a certain proportion of the particles (for example 90%) must fall below a certain size (for example 32 ⁇ m). For a quantitative determination of ingredients it is also essential that the analysis is based on a well-defined sample size.
  • a controlled automatic vibratory mill can have a metering device for feeding the milling unit with regrind and auxiliaries in always exactly defined quantity. After an adjustable grinding time (so-called grinding phase), the ground sample material is emptied into a sample collecting container during an adjustable discharge phase.
  • compositions of the material to be ground it may, in particular after the end of the grinding cycle in the automatic discharge to adhesions in the milling unit, in particular in the Austrags Schemeen the Grinding vessel, the discharge area and the spout come.
  • the discharge area and the spout come.
  • the adherences contaminate a subsequent sample and make it unusable for analysis.
  • attempts have been made to improve the uniqueness and reproducibility of the samples to be analyzed by cleaning all affected components in the machine after each grinding process in a customary manner so that contamination of a sample with waste material is reduced to a level permissible for the analysis becomes.
  • this cleaning requires a perceived as disadvantageous labor, time and thereby cost.
  • the object of the invention is to further develop a vibrating mill of the type mentioned above in terms of use, so that in particular the abovementioned disadvantages are reduced.
  • the vibrating mill speed change means suitable for predeterminable and insofar during operation independent, time-dependent change in the resulting or effective drive speed during operation of the vibratory mill or adapted.
  • attachments of regrind which can form at a low for the grinding itself drive speed or vibration frequency of the milling unit, by one or more brief changes in the grinding unit acting on the drive speed or frequency of the walls of Remove the vibrating mill, so that the expense for subsequent cleaning is eliminated or at least reduced.
  • the quality of the sample is reproducibly increased.
  • the favorable for the grinding itself drive speed or vibration frequency of the milling unit is on the one hand by the Sample material, in particular by its density, co-determined.
  • suitable for the grinding operation drive speed also depends on the design of the vibratory mill. While types in which the material to be ground between the filled into a grinding container, for example, spherical grinding media is subjected to a relatively high frequency, so-called.
  • Disc vibration mills in which within a bounded by a cylindrical grinding wall Mahlraumes a smaller diameter Mahlring and / or swing therein again, diameter-reduced circular grinding stone, operated due to the damage-sensitive structure at a relatively low frequency.
  • the invention preferably relates to such disk vibrating mills, but may also find application in other types, such as. Bechermahlmühlen find.
  • the oscillating drive has a drive motor, preferably an electric motor, and at least one thereof driven, preferably rotationally driven, imbalance.
  • the speed change means comprise a control device and / or a control device for controlling adjusting means for changing a drive rotational speed initially predetermined by the drive motor and / or for direct driving of the drive motor itself. If the speed change means act on said adjusting means, then a drive speed predetermined by the drive motor without such action can be changed, preferably reduced.
  • the drive motor for changing the drive speed or oscillation frequency can be directly controlled by the speed change means.
  • the drive firstly sets the grinding unit according to the introduced resultant drive speed in a specific vibration, the control or regulation on the respective composition of the ground material for the grinding process or the grinding phase is tuned. Starting from this basic or rated speed can then by means of the speed change means Preferably, towards the end or during the grinding process, the speed changed to the detachment of adhesions, preferably increased.
  • the oscillating drive by means of the speed change means, by means of therein contained electrical and / or electronic circuits and / or electrical and / or electronic storage means computer or program-based, is suitable for specifying at least one predetermined effective drive speed-time course.
  • a particularly high effectiveness for the removal of adhesions is achieved when the drive speed-time curve starting from a predetermined basic speed includes a one or more times increase to a maximum speed which is greater than or equal to a resonance speed at which the grinding unit excited to resonant vibrations becomes.
  • Preferred is a design of the vibrating mill, in which structurally conditioned the vibrations of the grinding unit and their discharge area (eg., An annular, located below the grinding floor discharge channel) and detect the outlet. If said change in the input rotational speed or oscillation frequency preferably acts on these regions to obtain a transient resonance, permanent attachments of ground sample material are prevented and a uniform, reproducibly complete discharge of the sample is made possible.
  • the selected maximum speed, up to which the drive speed is increased is greater than the speed causing the resonance (so-called resonance speed). It is possible that the drive speed-time curve has a holding phase of this maximum speed or that the speed is lowered immediately after reaching the maximum speed again. It is preferred that the drive speed-time curve after a rise to the maximum speed, a return to the base speed and thereafter preferably has a renewed holding phase of the base speed. It is considered appropriate that the drive speed-time curve cyclically has a multiple increase from the basic speed to the maximum speed.
  • the repeated repetition further improves the detachment of adhesions. It is also preferred that in accordance with the resulting drive speed-time course of a grinding phase and a Austragsphase ever a base speed (either equal or different) is assigned and that in the grinding phase and / or in the Austragsphase each at least an increase in the input speed of the basic speed a maximum speed is included.
  • the speed change means comprise electrical, mechanical, electromechanical, pneumatic, hydraulic and / or magnetic, preferably electromagnetic, speed change control means.
  • an electric adjusting means comes, for example, in an AC drive motor, a frequency converter, in a DC drive motor, a power converter into consideration.
  • a mechanical adjusting means for example, a mechanical brake is suitable, which acts on a driven by the drive motor shaft or components mounted thereon.
  • a pneumatic actuator is, for example, a pneumatic brake into consideration.
  • a hydraulic brake, an eddy current brake, an electromagnetically acting brake, etc. use.
  • the speed change means change the drive speed by means of electrical, mechanical, electromechanical, pneumatic, hydraulic and magnetic, preferably electromagnetic damping.
  • a high, in particular the said maximum speed corresponding drive speed of the drive motor can be lowered by the speed caused by the speed change means damping during the grinding and / or Austrags convinceds the vibratory mill initially to said basic speed.
  • the control may cause the damping to be canceled at a desired time or decreased in a controlled manner, thereby reducing the damping resulting drive speed increases up to the maximum speed.
  • the adjusting means are in turn suitable for increasing the drive speed, for example. It may be an electric, pneumatic or similar motor.
  • the speed change means automatically change the resulting drive speed and thus also the vibration of the grinding unit in the predetermined course after appropriate adjustment in operation at the desired time linearly and / or nonlinearly. Depending on the course, the resonance vibration of the grinding unit and the discharge unit is traversed in a defined manner or controlled approached and controlled leave again. It is also possible that the speed change means are designed as a module of the vibratory mill.
  • the speed change means may provide for cyclically varying the drive speeds of the drive unit during the milling operation and / or during the discharge phase of the sample from the milling unit.
  • the vibrating mill has a cooling device acting in particular on the grinding wall surrounding the grinding space.
  • cooling grooves for the flow of a coolant such as water, may be present. This is based on the found finding that without such cooling, especially during prolonged grinding operation by the frictional heat for heating the ground material and the walls of the grinding chamber can occur, whereby the tendency to buildup is increased.
  • the proposed cooling thus further contributes to the reduction of unwanted adhesions.
  • the invention also relates to a method for operating a vibrating mill, preferably a disc vibrating mill, which has a grinding unit and a vibrating drive, wherein the grinding unit is excited by the oscillating drive to oscillations dependent on their driving speed.
  • the invention has the object, advantageously further develop such a method, so that in particular adhesions of material to be ground in the vibrating mill avoided or at least reduced.
  • the driving speed is changed in a predetermined manner during the operation of the vibrating mill.
  • the drive speed is automatically changed according to a predetermined drive speed-time history.
  • the effective or resulting input speed may be increased one or more times from a base speed up to a selected maximum speed greater than or equal to a resonance speed at which the grinding unit is excited to resonate.
  • the drive speed for a desired defined time interval can be maintained at the maximum speed.
  • the drive speed can be lowered again to the base speed after an increase to the maximum speed and preferably maintained at the base speed for a further time interval.
  • the resulting drive speed can be cyclically increased several times from the basic speed to the maximum speed and lowered again to the basic speed.
  • a distinction can be made automatically between a grinding phase in which the millbase is comminuted and a discharge phase in which the millbase is discharged from the vibrating mill. It is preferred that in the grinding phase and / or in the discharge phase, the effective drive speed of an associated basic speed, which differ between the grinding and discharge phase or the same in each case Value is increased to a maximum speed that is greater than or equal to the resonance speed.
  • the change in the drive speed can be carried out appropriately by means of an electrical, mechanical, electro-mechanical, pneumatic, hydraulic and / or magnetic, preferably electromagnetic damping, but alternatively also by an active increase of a predetermined by a drive motor drive speed by means of an auxiliary drive. It is possible to change the drive speed and thus also the oscillation frequency of the milling unit linearly and / or nonlinearly.
  • the grinding unit preferably the grinding wall which surrounds the grinding space, can be cooled.
  • FIG. 1 shows in a cross section the upper portion of a vibrating mill 1 according to the invention according to a preferred embodiment.
  • An overall view, partly schematic, shows FIG. 3 This is a so-called disc vibratory mill.
  • mowing unit 2 represents one of a separate, connected to the milling unit vibratory drive vibratable assembly which includes a grinding chamber 3, which is externally bounded by a cylindrical grinding wall 4.
  • a substantially circular grinding soil 5 at At this bottom side during the grinding operation includes a substantially circular grinding soil 5 at.
  • Mahletti a Mahlring 6 and a millstone 7, which is a round, not cut in the illustration solid body, on.
  • the outer diameter of the Mahlringes 6 is smaller than the inner diameter of the grinding wall 4, and the outer diameter of the grinding stone 7 is smaller than the inner diameter of the Mahlringes 6.
  • Mahlspalt 8 and the Mahlspalt formed between Mahlring 6 and Mahlstein 7 9 allow a lateral relative movement of Mahlring 6 and millstone 7 both to each other and with respect to the grinding wall 4.
  • Mahldeckel 10 is sealed on the top side.
  • the vertical distance between the grinding base 5 and the grinding cover 10 is only slightly greater than the height of the grinding ring 6 and the grinding stone 7, so that just the desired Game for the lateral movement arises.
  • To the grinding wall 4 includes radially outside a housing ring 11, which is bolted to the underside with a housing base 12 and thereby connected to a drive flange 13.
  • the housing ring 11 On the upper side, the housing ring 11 is screwed to a housing cover 14.
  • Its underside has a recess 15, in which edge a seal 16, in the example chosen an O-ring, and in a Mahldeckel 17 are used.
  • the underside of the housing cover 14, the seal 16 and the grinding lid 17 are pressed against the upper end face of the grinding wall 4 by the clamping force of cover screws 18 distributed along the circumference.
  • the housing cover 14 and the grinding lid 17 have off-center passage openings for forming an entry opening 19. Through this, the grinding stock (not shown) to be comminuted can be filled into the grinding chamber 3 from above, where it is distributed in the grinding gaps 8, 9. If, as described below, lateral oscillatory movements of the grinding elements 6, 7 occur, the grinding gaps 8, 9 locally change their width, whereby the material to be ground between the grinding elements 6, 7 and the grinding wall 4 is ground.
  • the grinding wall 4, the grinding ring 6 and the grinding stone 7 may be made of a particularly suitable, in particular made of a hard material, while for the housing ring 11 and the other housing parts a conventional construction material, for example. Steel or light metal can be used.
  • a bracket 20 is screwed on the underside, which carries with its free end a cylinder 21 shown in simplified form, whose upper side protruding piston 22 is fastened by screwing to the grinding base 5 on the underside.
  • the cylinder 21 has two ports 23, 24 for supplying a pressurized fluid, such as air or hydraulic fluid.
  • FIG. 1 shown operating position is supplied through the lower port 24, a pressure medium, which acts in the interior of the cylinder 21, a pressure surface of the piston 22, not shown from below and presses it with the grinding soil 5 up until the grinding soil 5 at a stage 25 in positive engagement with the Grinding wall 4 occurs.
  • a pressure medium which acts in the interior of the cylinder 21, a pressure surface of the piston 22, not shown from below and presses it with the grinding soil 5 up until the grinding soil 5 at a stage 25 in positive engagement with the Grinding wall 4 occurs.
  • the stage 25 occurs against a lower chamfer 26 of the grinding wall 4 and a subsequent step 25 adjacent portion of the grinding tray 5 fits into the enclosed by the grinding wall 4 cross-section, the grinding chamber 3 is sealed during the grinding operation along the outer periphery of its grinding floor.
  • FIG. 1 Furthermore, it can be seen that the grinding unit 2 is equipped with a cooling device for the rear side or external cooling of the grinding wall 4.
  • this comprises two cooling grooves 47 adjoining the grinding wall 4 at the back, which are introduced into the inner wall surface 48 of the casing ring 11 supporting the grinding wall 4 on the outside.
  • the upper and lower cooling grooves 47 which extend in the circumferential direction from a coolant inlet 49 to a circumferentially spaced by about 10 °, not shown in the drawing flow for the coolant, are spaced by a likewise ring-segment-like support projection 50 which in Area of inlet and outlet is interrupted.
  • the inlet and outlet are separated by flow in the circumferential direction, so that a targeted circulation of coolant, which can be regulated, for example, to a desired temperature, is possible.
  • FIG. 2 shows comparatively a second operating position in which the upper port 23 is acted upon by a pressurized fluid.
  • a pressure application surface of the piston 22 is acted upon from above in a manner not shown, so that the piston 22 pulls the grinding base 5 down until it enters a defined positive stop with a collar 27 of the housing base 12.
  • lowered operating position arises between the grinding floor 5 and the grinding wall 4, a circumferentially extending gap 28, through which the grinding material comminuted during grinding due to the centrifugal forces occurring in a further vibration excitation in an annular discharge channel 29 and also therein according to vibration excitation up to an outlet opening 30 to an outlet 31 passes.
  • the discharge channel 29 is radially inwardly delimited by the grinding base 5, the underside by a resiliently supported thereon seal 32 and the housing base 12 and radially outside of the housing base 12, while at the top of the housing ring 11 and the grinding wall 4 connect.
  • the thus formed cross-section of the discharge channel 29 is offset with respect to the grinding chamber obliquely downward / radially outside.
  • FIG. 3 schematically illustrates that in the FIGS. 1 and 2 described grinding unit 2 of the vibratory mill 1 on the drive flange 13 is supported on the underside by means of spring-damper elements 33 on a solid surface.
  • an oscillating drive 34 is flange-mounted on the underside by means of screw connections.
  • this has a drive motor 35, here an electric motor, on whose shaft 36 rotates in an overlying housing 37 to the shaft 36 off-center, known per se and therefore illustrated simplified unbalance 40.
  • the torsional vibration generated in this way is transmitted via the drive flange 13 to the connected entire milling unit 2, including all involved in the grinding process and the discharge process of the ground material walls.
  • FIG. 3 schematically a control device 38, which is part of speed change means 39 according to the invention.
  • the motor 35 is fed by a device not shown with an operating voltage, which is first assigned to a specific drive speed of the shaft.
  • the control device 38 is suitable for driving with adjusting means 41 arranged in the housing 37 in a predetermined, temporally variable manner.
  • the adjusting means 41 are a brake which acts on the eccentric unbalance 40 from two opposite sides and which is indicated schematically.
  • a desired characteristic can be preselected by means of a control panel 42, which determines either the time profile of the control of the actuating means 41 or a characteristic curve which immediately corresponds to a desired resulting curve of the resulting drive speed over time.
  • the control signals are transmitted via a line 43 to the adjusting means 41 and translated in the example in a suitable form in a corresponding, time-varying compressive force with which the brake piston delaying the unbalance 40 occur.
  • the controller 38 may also communicate with the motor 35 directly, for example.
  • a speed signal is fed.
  • the controller 38 is adapted to the operator display on a display 45 directly from the selected settings resulting on the milling unit acting drive speed-time curve 46, wherein the drive speed U via the time t is applied.
  • FIG. 3 will be in conjunction with the FIGS.
  • FIGS. 4a-4c show various examples of preferred drive speed-time profiles 46.
  • the vibration drive at time t 1 is turned on, ie the operation begins.
  • the resulting from the motor voltage input speed U max is equal to the beginning of the activated actuating means 41 (brake) lowered to a desired for the grinding operation base speed U nenn .
  • the effect of the actuating means 41 is linearly reduced starting from the time t 2 to t 3 by means of the controller 38 until the effective drive speed U corresponds to the maximum speed U max .
  • a speed value U Res is passed, in which the grinding unit 2 is excited to resonant vibrations.
  • the resonance speed U Res is passed through controlled.
  • the basic rotational speed U nenn is maintained for a further time interval t 4 -t 5 and the grinding process is ended at t 5 .
  • the base speed U nenn example.
  • the resonance speed is, for example, in the range of 1000-1100 U / min, and reached the maximum speed U max is, for example, 1300 rpm.
  • the maximum speed U max is, for example, 1300 rpm.
  • FIG. 4b shows a second embodiment in which the resonance speed is also traversed linearly in total trapezoidal resulting drive speed-time course 46.
  • FIG. 4a shows during the grinding time t 1 - t 5 a total of two evenly distributed fürfahrungszyklen provided.
  • Figure 4c shows a third preferred embodiment. The resonance speed is traversed here in three cycles with rounded course, similar to harmonic areas with interruptions.

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  • Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Crushing And Grinding (AREA)
  • Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)

Description

Die vorliegende Erfindung betrifft eine Schwingmühle, vorzugsweise eine Scheibenschwingmühle, aufweisend eine Mahleinheit und einen Schwingantrieb, mittels dem die Mahleinheit zu von der Antriebsdrehzahl des Schwingantriebs abhängigen Schwingungen anregbar ist.The present invention relates to a vibrating mill, preferably a disc vibrating mill, comprising a grinding unit and a vibrating drive, by means of which the grinding unit can be excited to vibrations dependent on the driving speed of the vibrating drive.

Derartige Schwingmühlen dienen insbesondere zur mahlenden Zerkleinerung einer Probe aus schüttfähigem, körnigem Mahlgut im Zuge der Vorbereitung der Probe für gewünschte Analysen, bspw. für röntgenbasierende Untersuchungen der enthaltenen Elemente mit geeigneten Anlagen (z. B. XRF). Eine derartige Schwingmühle ist aus der US5733173 bekannt. Auch Mahlgut, das von einer Flüssigkeit in den Mahlraum gespült wird, ist denkbar. Die Probe, bei der es sich bspw. um eine Gesteinsprobe, um Erz, Schlacke usw. handeln kann, wird in der Schwingmühle mit Hilfsstoffen gemischt und zermahlen und dann mit Presshilfszugaben zu einer Tablette verpresst, die einem Analysegerät zur Analyse der Bestandteile zugeführt wird. Die Probe muss so zerkleinert werden, dass alle Bestandteile eine homogene Mischung ergeben, wofür eine feine und gleichmäßige Zerkleinerung des Mahlgutes in der Schwingmühle wesentlich ist. Häufig wird verlangt, dass nach dem Mahlvorgang ein bestimmter Anteil der Partikel (bspw. 90 %) eine bestimmte Größe (bspw. 32 µm) unterschreiten muss. Für eine quantitative Bestimmung von Inhaltsstoffen ist außerdem wesentlich, dass der Analyse eine genau bestimmte Probenmenge zugrunde liegt. Dazu kann eine gesteuerte automatische Schwingmühle eine Dosiereinrichtung für die Beschickung der Mahleinheit mit Mahlgut und Hilfsmittel in immer exakt definierter Menge aufweisen. Nach Ablauf einer einstellbaren Mahldauer (sog. Mahlphase) wird das gemahlene Probenmaterial während einer einstellbaren Austragsphase in einen Probenauffangbehälter entleert. Bei einigen Zusammensetzungen des Mahlgutes kann es insbesondere nach dem Ende des Mahlganges beim automatischen Austrag zu Anhaftungen in der Mahleinheit, insbesondere in den Austragsbereichen des Mahlgefäßes, dem Austragsbereich und dem Auslauf kommen. Das hat zur Folge, dass nicht die gesamte Probenmenge zur Analyse zur Verfügung steht und somit das Analyseergebnis verfälscht werden kann. Zudem besteht die Gefahr, dass durch die Anhaftungen eine nachfolgende Probe kontaminiert und für die Analyse unbrauchbar gemacht wird. Bisher wird versucht, die Eindeutigkeit und Reproduzierbarkeit der zu analysierenden Proben dadurch zu verbessern, dass nach jedem Mahlprozess in üblicher Weise eine Reinigung aller betroffenen Bauteile in der Maschine derart durchgeführt wird, dass eine Kontaminierung einer Probe mit Altmaterial auf ein für die Analyse zulässiges Maß verringert wird. Diese Reinigung bedingt aber einen als nachteilig empfundenen Arbeits-, Zeit- und dadurch Kostenaufwand.Such vibratory mills are used in particular for grinding a sample of free-flowing, granular ground material in the course of preparing the sample for desired analyzes, for example for X-ray-based investigations of the elements contained with suitable equipment (eg XRF). Such a vibratory mill is from the US5733173 known. Also regrind, which is rinsed by a liquid in the grinding chamber, is conceivable. The sample, which may be, for example, a rock sample, ore, slag, etc., is mixed and ground in the vibratory mill with excipients and then pressed with auxiliaries to a tablet which is fed to an analyzer for analysis of the ingredients. The sample must be crushed in such a way that all components give a homogeneous mixture, for which a fine and uniform comminution of the material to be ground in the vibratory mill is essential. Often it is required that after the grinding process, a certain proportion of the particles (for example 90%) must fall below a certain size (for example 32 μm). For a quantitative determination of ingredients it is also essential that the analysis is based on a well-defined sample size. For this purpose, a controlled automatic vibratory mill can have a metering device for feeding the milling unit with regrind and auxiliaries in always exactly defined quantity. After an adjustable grinding time (so-called grinding phase), the ground sample material is emptied into a sample collecting container during an adjustable discharge phase. In some compositions of the material to be ground, it may, in particular after the end of the grinding cycle in the automatic discharge to adhesions in the milling unit, in particular in the Austragsbereichen the Grinding vessel, the discharge area and the spout come. As a result, not all the sample quantity is available for analysis and thus the analysis result can be falsified. In addition, there is a risk that the adherences contaminate a subsequent sample and make it unusable for analysis. Heretofore, attempts have been made to improve the uniqueness and reproducibility of the samples to be analyzed by cleaning all affected components in the machine after each grinding process in a customary manner so that contamination of a sample with waste material is reduced to a level permissible for the analysis becomes. However, this cleaning requires a perceived as disadvantageous labor, time and thereby cost.

Davon ausgehend liegt der Erfindung die Aufgabe zugrunde, eine Schwingmühle der eingangs genannten Art gebrauchsvorteilhaft weiterzubilden, so dass insbesondere die vorgenannten Nachteile verringert werden.Based on this, the object of the invention is to further develop a vibrating mill of the type mentioned above in terms of use, so that in particular the abovementioned disadvantages are reduced.

Die Aufgabe ist gemäß der Erfindung zunächst und im wesentlichen in Verbindung mit den Merkmalen des Anspruchs 1 gelöst, dass die Schwingmühle Drehzahländerungsmittel aufweist, die zur vorbestimmbaren und insofern während des Betriebs selbstständigen, zeitabhängigen Änderung der resultierenden bzw. wirksamen Antriebsdrehzahl während des Betriebs der Schwingmühle geeignet bzw. angepasst sind. Dem liegt die gefundene Erkenntnis zugrunde, dass sich Anhaftungen von Mahlgut, die sich bei einer für den Mahlvorgang selbst günstigen Antriebsdrehzahl bzw. Schwingungsfrequenz der Mahleinheit bilden können, durch eine oder mehrere kurzzeitige Änderungen der auf die Mahleinheit einwirkenden Antriebsdrehzahl bzw. Frequenz von den Wandungen der Schwingmühle ablösen lassen, so dass der Aufwand für eine nachfolgende Reinigung entfällt oder zumindest verringert wird. Die Qualität der Probe wird reproduzierbar gesteigert. Die für den Mahlvorgang selbst günstige Antriebsdrehzahl bzw. Schwingfrequenz der Mahleinheit wird einerseits durch das Probenmaterial, insbesondere durch dessen Dichte, mitbestimmt. Anderseits hängt die für den Mahlbetrieb geeignete Antriebsdrehzahl auch von der Bauart der Schwingmühle ab. Während Bauarten, bei welchen das Mahlgut zwischen den in einen Mahlbehälter eingefüllten, bspw. kugelartigen Mahlkörpern zerrieben wird, eine vergleichsweise hohe Frequenz ertragen, werden sog. Scheibenschwingmühlen, bei welchen innerhalb eines von einer zylindrischen Mahlwand berandeten Mahlraumes ein im Durchmesser kleinerer Mahlring und/oder ein darin befindlicher, nochmals durchmesserverringerter kreisförmiger Mahlstein schwingen, aufgrund des für Beschädigungen empfindlichen Aufbaus bei vergleichsweise niedriger Frequenz betrieben. Die Erfindung betrifft vorzugsweise derartige Scheibenschwingmühlen, kann aber auch Anwendung bei anderen Bauformen, wie bspw. Bechermahlmühlen, finden. Bevorzugt ist, dass der Schwingantrieb einen Antriebsmotor, vorzugsweise einen Elektromotor, und zumindest eine davon angetriebene, vorzugsweise drehangetriebene, Unwucht aufweist. Als zweckmäßig wird angesehen, dass die Drehzahländerungsmittel eine Steuerungseinrichtung und/oder eine Regelungseinrichtung zur Ansteuerung von Stellmitteln zur Änderung einer zunächst vom Antriebsmotor vorgegebenen Antriebsdrehzahl und/oder zur direkten Ansteuerung des Antriebsmotors selbst aufweisen. Wirken die Drehzahländerungsmittel auf besagte Stellmittel ein, kann darüber eine von dem Antriebsmotor ohne eine solche Einwirkung vorgegebene Antriebsdrehzahl verändert, vorzugsweise verringert werden. Alternativ kann der Antriebsmotor zur Veränderung der Antriebsdrehzahl bzw. Schwingungsfrequenz von den Drehzahländerungsmitteln unmittelbar angesteuert werden. In beiden Fällen besteht die Möglichkeit, dass an einer automatischen Schwingmühle, vorzugsweise Scheibenschwingmühle, der Antrieb die Mahleinheit entsprechend der eingebrachten resultierenden Antriebsdrehzahl zunächst in eine spezifische Schwingung versetzt, die steuerungs- oder regelungsmäßig auf die jeweilige Zusammensetzung des Mahlgutes für den Mahlvorgang bzw. die Mahlphase abgestimmt ist. Von dieser Grund- bzw. Nenn-Drehzahl ausgehend kann dann mittels der Drehzahländerungsmittel vorzugsweise gegen Ende oder auch während des Mahlvorganges die Drehzahl zur Ablösung von Anhaftungen verändert, vorzugsweise erhöht, werden. Es besteht die Möglichkeit, dass der Schwingantrieb mittels der Drehzahländerungsmittel, mittels darin enthaltener elektrischer und/oder elektronischer Schaltungen und/oder elektrischer und/ oder elektronischer Speichermittel rechner- bzw. programmgestützt, zur Vorgabe zumindest eines vorbestimmten wirksamen Antriebsdrehzahl-Zeit-Verlaufes geeignet ist. Eine besonders hohe Wirksamkeit zur Ablösung von Anhaftungen wird erreicht, wenn der Antriebsdrehzahl-Zeit-Verlauf ausgehend von einer vorbestimmten Grunddrehzahl einen ein- oder mehrmaligen Anstieg zu einer Maximaldrehzahl beinhaltet, welche größer oder etwa gleich einer Resonanzdrehzahl ist, bei welcher die Mahleinheit zu Resonanzschwingungen angeregt wird. Bevorzugt ist eine Bauweise der Schwingmühle, bei welcher konstruktiv bedingt die Schwingungen der Mahleinheit auch deren Austragsbereich (bspw. einen ringförmigen, unterhalb des Mahlbodens befindlichen Austragskanal) und den Auslauf erfassen. Wirkt auf diese Bereiche besagte Veränderung der Antriebsdrehzahl bzw. Schwingfrequenz vorzugsweise unter Erzielung einer vorübergehenden Resonanz ein, werden bleibende Anhaftungen von gemahlenem Probenmaterial verhindert und ein gleichmäßiges, reproduzierbar vollständiges Austragen der Probe ermöglicht. Dabei wurde gefunden, dass zum Ablösen von Anhaftungen bereits das sehr kurzzeitige Durchfahren der Resonanzfrequenz bzw. Resonanzschwingung äußerst wirksam ist. Um insbesondere an Scheibenschwingmühlen Beschädigungen zu vermeiden, ist daher bevorzugt, dass die gewählte Maximaldrehzahl, bis zu der die Antriebsdrehzahl gesteigert wird, größer als die Resonanz bewirkende Drehzahl (sog. Resonanzdrehzahl) ist. Es besteht die Möglichkeit, dass der Antriebsdrehzahl-Zeit-Verlauf eine Haltephase dieser Maximaldrehzahl aufweist oder dass die Drehzahl nach Erreichen der Maximaldrehzahl sogleich wieder abgesenkt wird. Bevorzugt ist, dass der Antriebsdrehzahl-Zeit-Verlauf nach einem Anstieg auf die Maximaldrehzahl eine Rückkehr auf die Grunddrehzahl und daran anschließend vorzugsweise eine erneute Haltephase der Grunddrehzahl aufweist. Als zweckmäßig wird angesehen, dass der Antriebsdrehzahl-Zeit-Verlauf zyklisch einen mehrfachen Anstieg von der Grunddrehzahl zu der Maximaldrehzahl aufweist. Durch die mehrfache Wiederholung wird die Ablösung von Anhaftungen weiter verbessert. Bevorzugt ist außerdem, dass gemäß dem resultierenden Antriebsdrehzahl- Zeit-Verlauf einer Mahlphase und einer Austragsphase je eine Grunddrehzahl (entweder gleich oder unterschiedlich) zugeordnet ist und dass in der Mahlphase und/ oder in der Austragsphase jeweils zumindest ein Anstieg der Antriebsdrehzahl von der Grunddrehzahl auf eine Maximaldrehzahl enthalten ist. Es besteht die Möglichkeit, dass die Drehzahländerungsmittel elektrische, mechanische, elek-tromechanische, pneumatische, hydraulische und/magnetische, vorzugsweise elektromagnetische, Stellmittel zur Drehzahländerung aufweisen. Als elektrisches Stellmittel kommt bspw. bei einem Wechselstrom-Antriebsmotor ein Frequenzumrichter, bei einem Gleichstrom-Antriebsmotor ein Stromrichter in Betracht. Als mechanisches Stellmittel ist zum Beispiel eine mechanische Bremse geeignet, die auf eine von dem Antriebsmotor angetriebene Welle oder darauf befestigte Bauteile einwirkt. Als pneumatisches Stellmittel kommt bspw. eine pneumatische Bremse in Betracht. Alternativ lassen sich gemäß den weiter aufgezählten Möglichkeiten bspw. eine hydraulische Bremse, eine Wirbelstrombremse, eine elektromagnetisch wirkende Bremse usw. einsetzen. In diesem Zusammenhang ist bevorzugt, dass die Drehzahländerungsmittel die Antriebs-Drehzahl mittels einer elektrischen, mechanischen, elektromechanischen, pneumatischen, hydraulischen und magnetischen, vorzugsweise elektromagnetischen Dämpfung verändern. Eine hohe, insbesondere der besagten Maximaldrehzahl entsprechende Antriebsdrehzahl des Antriebsmotors kann durch die von den Drehzahländerungsmitteln bewirkte Dämpfung während des Mahl- und/oder Austragsbetriebs der Schwingmühle zunächst auf die besagte Grunddrehzahl abgesenkt werden. Die Steuerung bzw. Regelung kann veranlassen, dass die Dämpfung zu gewünschter Zeit aufgehoben oder in kontrollierter Weise verringert wird, wodurch die resultierende Antriebsdrehzahl bis zu der Maximaldrehzahl ansteigt. Alternativ besteht die Möglichkeit, dass die Stellmittel ihrerseits zur Erhöhung der Antriebsdrehzahl geeignet sind, bspw. kann es sich um einen elektrischen, pneumatischen oder dergleichen Motor handeln. Es besteht die Möglichkeit, dass die Drehzahländerungsmittel die resultierende Antriebsdrehzahl und somit auch die Schwingung der Mahleinheit in dem vorbestimmten Verlauf nach entsprechender Einstellung im Betrieb zu gewünschter Zeit selbstständig linear und/oder nichtlinear verändern. Je nach Verlauf wird die Resonanzschwingung der Mahleinheit und der Austragseinheit in definierter Weise durchfahren bzw. kontrolliert angefahren und kontrolliert wieder verlassen. Auch besteht die Möglichkeit, dass die Drehzahländerungsmittel als Modul der Schwingmühle ausgeführt sind. In der automatisierten Schwingmühle können die Drehzahländerungsmittel, das Modul für die zyklische Veränderung der Antriebsdrehzahlen der Antriebseinheit während des Mahlbetriebs und/oder während der Austragsphase der Probe aus der Mahleinheit sorgen. Alternativ oder kombinativ ist bevorzugt, dass die Schwingmühle eine insbesondere auf die den Mahlraum umgebende Mahlwand einwirkende Kühleinrichtung aufweist. Beispielsweise können Kühlnuten zum Durchfluss eines Kühlmittels, wie bspw. Wasser, vorhanden sein. Dem liegt die gefundene Erkenntnis zugrunde, dass es ohne eine solche Kühlung besonders bei längerem Mahlbetrieb durch die Reibungswärme zur Erwärmung des Mahlguts und der Wandungen des Mahlraumes kommen kann, wodurch die Neigung zu Anhaftungen vergrößert wird. Durch die vorgeschlagene Kühlung wird somit ein weiterer Beitrag zur Verringerung der unerwünschten Anhaftungen geleistet.The object is achieved according to the invention first and essentially in conjunction with the features of claim 1, that the vibrating mill speed change means suitable for predeterminable and insofar during operation independent, time-dependent change in the resulting or effective drive speed during operation of the vibratory mill or adapted. This is based on the found finding that attachments of regrind, which can form at a low for the grinding itself drive speed or vibration frequency of the milling unit, by one or more brief changes in the grinding unit acting on the drive speed or frequency of the walls of Remove the vibrating mill, so that the expense for subsequent cleaning is eliminated or at least reduced. The quality of the sample is reproducibly increased. The favorable for the grinding itself drive speed or vibration frequency of the milling unit is on the one hand by the Sample material, in particular by its density, co-determined. On the other hand, suitable for the grinding operation drive speed also depends on the design of the vibratory mill. While types in which the material to be ground between the filled into a grinding container, for example, spherical grinding media is subjected to a relatively high frequency, so-called. Disc vibration mills, in which within a bounded by a cylindrical grinding wall Mahlraumes a smaller diameter Mahlring and / or swing therein again, diameter-reduced circular grinding stone, operated due to the damage-sensitive structure at a relatively low frequency. The invention preferably relates to such disk vibrating mills, but may also find application in other types, such as. Bechermahlmühlen find. It is preferred that the oscillating drive has a drive motor, preferably an electric motor, and at least one thereof driven, preferably rotationally driven, imbalance. It is considered appropriate that the speed change means comprise a control device and / or a control device for controlling adjusting means for changing a drive rotational speed initially predetermined by the drive motor and / or for direct driving of the drive motor itself. If the speed change means act on said adjusting means, then a drive speed predetermined by the drive motor without such action can be changed, preferably reduced. Alternatively, the drive motor for changing the drive speed or oscillation frequency can be directly controlled by the speed change means. In both cases, there is the possibility that on an automatic vibratory mill, preferably disc vibratory mill, the drive firstly sets the grinding unit according to the introduced resultant drive speed in a specific vibration, the control or regulation on the respective composition of the ground material for the grinding process or the grinding phase is tuned. Starting from this basic or rated speed can then by means of the speed change means Preferably, towards the end or during the grinding process, the speed changed to the detachment of adhesions, preferably increased. There is the possibility that the oscillating drive by means of the speed change means, by means of therein contained electrical and / or electronic circuits and / or electrical and / or electronic storage means computer or program-based, is suitable for specifying at least one predetermined effective drive speed-time course. A particularly high effectiveness for the removal of adhesions is achieved when the drive speed-time curve starting from a predetermined basic speed includes a one or more times increase to a maximum speed which is greater than or equal to a resonance speed at which the grinding unit excited to resonant vibrations becomes. Preferred is a design of the vibrating mill, in which structurally conditioned the vibrations of the grinding unit and their discharge area (eg., An annular, located below the grinding floor discharge channel) and detect the outlet. If said change in the input rotational speed or oscillation frequency preferably acts on these regions to obtain a transient resonance, permanent attachments of ground sample material are prevented and a uniform, reproducibly complete discharge of the sample is made possible. It was found that the very short-term passage through the resonance frequency or resonance oscillation is extremely effective for detaching adhesions. In order to avoid damages, in particular on disc vibrating mills, it is therefore preferred that the selected maximum speed, up to which the drive speed is increased, is greater than the speed causing the resonance (so-called resonance speed). It is possible that the drive speed-time curve has a holding phase of this maximum speed or that the speed is lowered immediately after reaching the maximum speed again. It is preferred that the drive speed-time curve after a rise to the maximum speed, a return to the base speed and thereafter preferably has a renewed holding phase of the base speed. It is considered appropriate that the drive speed-time curve cyclically has a multiple increase from the basic speed to the maximum speed. The repeated repetition further improves the detachment of adhesions. It is also preferred that in accordance with the resulting drive speed-time course of a grinding phase and a Austragsphase ever a base speed (either equal or different) is assigned and that in the grinding phase and / or in the Austragsphase each at least an increase in the input speed of the basic speed a maximum speed is included. There is the possibility that the speed change means comprise electrical, mechanical, electromechanical, pneumatic, hydraulic and / or magnetic, preferably electromagnetic, speed change control means. As an electric adjusting means comes, for example, in an AC drive motor, a frequency converter, in a DC drive motor, a power converter into consideration. As a mechanical adjusting means, for example, a mechanical brake is suitable, which acts on a driven by the drive motor shaft or components mounted thereon. As a pneumatic actuator is, for example, a pneumatic brake into consideration. Alternatively, according to the further enumerated possibilities, for example, a hydraulic brake, an eddy current brake, an electromagnetically acting brake, etc. use. In this connection it is preferred that the speed change means change the drive speed by means of electrical, mechanical, electromechanical, pneumatic, hydraulic and magnetic, preferably electromagnetic damping. A high, in particular the said maximum speed corresponding drive speed of the drive motor can be lowered by the speed caused by the speed change means damping during the grinding and / or Austragsbetriebs the vibratory mill initially to said basic speed. The control may cause the damping to be canceled at a desired time or decreased in a controlled manner, thereby reducing the damping resulting drive speed increases up to the maximum speed. Alternatively, there is the possibility that the adjusting means are in turn suitable for increasing the drive speed, for example. It may be an electric, pneumatic or similar motor. There is the possibility that the speed change means automatically change the resulting drive speed and thus also the vibration of the grinding unit in the predetermined course after appropriate adjustment in operation at the desired time linearly and / or nonlinearly. Depending on the course, the resonance vibration of the grinding unit and the discharge unit is traversed in a defined manner or controlled approached and controlled leave again. It is also possible that the speed change means are designed as a module of the vibratory mill. In the automated vibratory mill, the speed change means, the module, may provide for cyclically varying the drive speeds of the drive unit during the milling operation and / or during the discharge phase of the sample from the milling unit. Alternatively or in combination, it is preferred that the vibrating mill has a cooling device acting in particular on the grinding wall surrounding the grinding space. For example, cooling grooves for the flow of a coolant, such as water, may be present. This is based on the found finding that without such cooling, especially during prolonged grinding operation by the frictional heat for heating the ground material and the walls of the grinding chamber can occur, whereby the tendency to buildup is increased. The proposed cooling thus further contributes to the reduction of unwanted adhesions.

Die Erfindung betrifft außerdem ein Verfahren zum Betrieb einer Schwingmühle, vorzugsweise einer Scheibenschwingmühle, welche eine Mahleinheit und einen Schwingantrieb aufweist, wobei die Mahleinheit von dem Schwingantrieb zu von deren Antriebsdrehzahl abhängigen Schwingungen angeregt wird. Ausgehend von der eingangs beschriebenen Problematik liegt der Erfindung die Aufgabe zugrunde, ein derartiges Verfahren vorteilhaft weiterzubilden, so dass insbesondere Anhaftungen von Mahlgut in der Schwingmühle vermieden oder zumindest reduziert werden.The invention also relates to a method for operating a vibrating mill, preferably a disc vibrating mill, which has a grinding unit and a vibrating drive, wherein the grinding unit is excited by the oscillating drive to oscillations dependent on their driving speed. Based on the problem described above, the invention has the object, advantageously further develop such a method, so that in particular adhesions of material to be ground in the vibrating mill avoided or at least reduced.

Die Aufgabe wird erfindungsgemäß durch die Merkmale des Anspruchs 10 gelöst. Die Antriebsdrehzahl wird während des Betriebs der Schwingmühle in vorbestimmter Weise verändert. Zu dadurch und durch die nachfolgend beschriebenen Merkmale möglichen Wirkungen und Vorteile wird auf die vorangehende Beschreibung Bezug genommen. Die Antriebsdrehzahl wird gemäß einem vorbestimmten Antriebsdrehzahl-Zeit-Verlauf automatisiert geändert. Es besteht die Möglichkeit, dass die wirksame bzw. resultierende Antriebsdrehzahl ausgehend von einer Grunddrehzahl ein- oder mehrmalig bis zu einer gewählten maximalen Drehzahl erhöht wird, die größer oder etwa gleich einer Resonanzdrehzahl ist, bei der die Mahleinheit zu Resonanzschwingungen angeregt wird. Auch kann die Antriebsdrehzahl für ein gewünschtes definiertes Zeitintervall auf Höhe der Maximaldrehzahl gehalten werden. Bei einer zweckmäßigen Ausführung des Verfahrens kann die Antriebsdrehzahl nach einer Erhöhung auf die Maximaldrehzahl wieder bis zur Grunddrehzahl abgesenkt und vorzugsweise für ein weiteres Zeitintervall auf der Grunddrehzahl gehalten werden. Um die Ablösung von Anhaftungen zu intensivieren, kann die resultierende Antriebsdrehzahl zyklisch mehrfach von der Grunddrehzahl auf die Maximaldrehzahl angehoben und wieder auf die Grunddrehzahl abgesenkt werden. Des weiteren kann bei dem Verfahren vorzugsweise automatisiert zwischen einer Mahlphase, in welcher das Mahlgut zerkleinert wird, und einer Austragsphase, in welcher das Mahlgut aus der Schwingmühle ausgetragen wird, unterschieden werden. Bevorzugt ist, dass in der Mahlphase und/oder in der Austragsphase die wirksame Antriebsdrehzahl von einer zugeordneten Grunddrehzahl, die sich zwischen Mahl- und Austragsphase unterscheiden oder den jeweils gleichen Wert besitzen kann, auf eine Maximaldrehzahl erhöht wird, die größer oder gleich der Resonanzdrehzahl ist. Zur Drehzahländerung können vorzugsweise elek-trische, mechanische, elektromechanische, pneumatische, hydraulische und/oder magnetische, vorzugsweise elektromagnetische Stellmittel verwendet werden. Die Änderung der Antriebsdrehzahl kann zweckmäßig mittels einer elektrischen, mechanischen, elektromechanischen, pneumatischen, hydraulischen und/ oder magnetischen, vorzugsweise elektromagnetischen Dämpfung erfolgen, alternativ aber auch durch eine aktive Erhöhung einer zunächst von einem Antriebsmotor vorgegebenen Antriebsdrehzahl mittels eines Zusatzantriebs. Es besteht die Möglichkeit, die Antriebsdrehzahl und somit auch die Schwingungsfrequenz der Mahleinheit linear und/oder nichtlinear zu verändern. Alternativ oder kombinativ kann die Mahleinheit, vorzugsweise die den Mahlraum berandende Mahlwand, gekühlt werden.The object is achieved by the features of claim 10. The driving speed is changed in a predetermined manner during the operation of the vibrating mill. For possible effects and advantages to be achieved therefrom and by the features described below, reference is made to the preceding description. The drive speed is automatically changed according to a predetermined drive speed-time history. There is a possibility that the effective or resulting input speed may be increased one or more times from a base speed up to a selected maximum speed greater than or equal to a resonance speed at which the grinding unit is excited to resonate. Also, the drive speed for a desired defined time interval can be maintained at the maximum speed. In an expedient embodiment of the method, the drive speed can be lowered again to the base speed after an increase to the maximum speed and preferably maintained at the base speed for a further time interval. To intensify the detachment of buildup, the resulting drive speed can be cyclically increased several times from the basic speed to the maximum speed and lowered again to the basic speed. Furthermore, in the method preferably a distinction can be made automatically between a grinding phase in which the millbase is comminuted and a discharge phase in which the millbase is discharged from the vibrating mill. It is preferred that in the grinding phase and / or in the discharge phase, the effective drive speed of an associated basic speed, which differ between the grinding and discharge phase or the same in each case Value is increased to a maximum speed that is greater than or equal to the resonance speed. To change the speed, it is possible to use preferably electrical, mechanical, electromechanical, pneumatic, hydraulic and / or magnetic, preferably electromagnetic, actuating means. The change in the drive speed can be carried out appropriately by means of an electrical, mechanical, electro-mechanical, pneumatic, hydraulic and / or magnetic, preferably electromagnetic damping, but alternatively also by an active increase of a predetermined by a drive motor drive speed by means of an auxiliary drive. It is possible to change the drive speed and thus also the oscillation frequency of the milling unit linearly and / or nonlinearly. Alternatively or in combination, the grinding unit, preferably the grinding wall which surrounds the grinding space, can be cooled.

Die Erfindung wird nachfolgend mit Bezug auf die beigefügten Zeichnungen, welche ein bevorzugtes Ausführungsbeispiel zeigen, näher beschrieben. Darin zeigt:

Fig. 1
eine erfindungsgemäße Mahleinheit einer Schwingmühle gemäß der vorliegenden Erfindung in einer bevorzugten Ausführungsform in einem Querschnitt, in der Einstellung für die Mahlphase;
Fig. 2
die Mahleinheit der Schwingmühle gemäß Fig. 1, in der Einstellung für die Austragsphase;
Fig. 3
die Schwingmühle der in den Fig. 1, 2 gezeigten Mahleinheit in Außenansicht, unter schematischer Darstellung des Schwingantriebs und von Drehzahländerungsmitteln und
Fig. 4a - 4c
verschiedene bevorzugte Ausführungsbeispiele von mittels der Drehzahländerungsmittel vorgegebenen Antriebsdrehzahl- Zeit-Verläufen.
The invention will be described in more detail below with reference to the accompanying drawings, which show a preferred embodiment. It shows:
Fig. 1
a grinding unit according to the invention of a vibrating mill according to the present invention in a preferred embodiment in a cross section, in the setting for the grinding phase;
Fig. 2
the mowing unit of the vibratory mill according to Fig. 1 , in the setting for the discharge phase;
Fig. 3
the vibrating mill in the Fig. 1 . 2 in external view, with a schematic representation of the vibratory drive and speed change means and
Fig. 4a - 4c
Various preferred embodiments of predetermined by means of the speed change means drive speed-time curves.

Figur 1 zeigt in einem Querschnitt den oberen Bereich einer erfindungsgemäßen Schwingmühle 1 gemäß einer bevorzugten Ausführungsform. Eine Gesamtansicht, teilweise schematisch, zeigt Figur 3. Dabei handelt es sich um eine sog. Scheibenschwingmühle. Deren in Figur 1 gezeigte Mahleinheit 2 stellt eine von einem gesonderten, an der Mahleinheit angeschlossenen Schwingantrieb zu Schwingungen anregbare Baugruppe dar, welche einen Mahlraum 3 einschließt, der außen von einer zylindrischen Mahlwand 4 berandet wird. An diese schließt unterseitig während des Mahlbetriebs ein im wesentlichen kreisförmiger Mahlboden 5 an. Auf diesem liegen in dem gezeigten Ausführungsbeispiel als Mahlelemente ein Mahlring 6 und ein Mahlstein 7, bei welchem es sich um einen runden, in der Darstellung nicht geschnittenen Vollkörper handelt, auf. Der Außendurchmesser des Mahlringes 6 ist kleiner als der Innendurchmesser der Mahlwand 4, und der Außendurchmesser des Mahlsteins 7 ist kleiner als der Innendurchmesser des Mahlringes 6. Der so zwischen Mahlwand 4 und Mahlring 6 gebildete Mahlspalt 8 und der zwischen Mahlring 6 und Mahlstein 7 gebildete Mahlspalt 9 ermöglichen eine seitliche Relativbewegung von Mahlring 6 und Mahlstein 7 sowohl zueinander als auch bezüglich der Mahlwand 4. An letztere schließt oberseitig abgedichtet ein Mahldeckel 10 an. In Figur 1, in der sich der Mahlboden 5 während der sog. Mahlphase in seiner oberen möglichen Position befindet, ist der vertikale Abstand zwischen Mahlboden 5 und Mahldeckel 10 nur geringfügig größer als die Höhe von Mahlring 6 und Mahlstein 7, so dass gerade das gewünschte Spiel für die seitliche Bewegung entsteht. An die Mahlwand 4 schließt radial außerhalb ein Gehäusering 11 an, der unterseitig mit einer Gehäusebasis 12 verschraubt und dadurch mit einem Antriebsflansch 13 verbunden ist. Oberseitig ist der Gehäusering 11 mit einem Gehäusedeckel 14 verschraubt. Dessen Unterseite weist eine Ausnehmung 15 auf, in welche randseitig eine Dichtung 16, im gewählten Beispiel ein O-Ring, und darin ein Mahldeckel 17 eingesetzt sind. Durch die Klemmkraft von entlang des Umfangs verteilten Deckelschrauben 18 werden die Unterseite des Gehäusedeckels 14, der Dichtung 16 und des Mahldeckels 17 gegen die obere Stirnseite der Mahlwand 4 gedrückt. Der Gehäusedeckel 14 und der Mahldeckel 17 weisen außermittig Durchgangsöffnungen zur Bildung einer Eintragsöffnung 19 auf. Durch diese kann das zu zerkleinernde Mahlgut (nicht dargestellt) in den Mahlraum 3 von oben eingefüllt werden, wo es sich in den Mahlspalten 8, 9 verteilt. Kommt es, wie noch nachfolgend beschrieben, zu seitlichen Schwingbewegungen der Mahlelemente 6, 7, ändern die Mahlspalte 8, 9 lokal laufend ihre Breite, wodurch das Mahlgut zwischen den Mahlelementen 6, 7 und der Mahlwand 4 zermahlen wird. Die Mahlwand 4, der Mahlring 6 und der Mahlstein 7 können aus einem dazu besonders geeigneten, insbesondere aus einem harten Werkstoff hergestellt sein, während sich für den Gehäusering 11 und die übrigen Gehäuseteile ein herkömmlicher Konstruktionswerkstoff, bspw. Stahl oder Leichtmetall, verwenden lässt. An der Gehäusebasis 12 ist unterseitig eine Halterung 20 angeschraubt, die mit ihrem freien Ende einen vereinfacht gezeigten Zylinder 21 trägt, dessen oberseitig herausstehender Kolben 22 mittels Verschraubung an dem Mahlboden 5 unterseitig befestigt ist. Der Zylinder 21 weist zwei Anschlüsse 23, 24 zur Zufuhr eines unter Druck stehenden Fluids, wie Luft oder einer Hydraulikflüssigkeit auf. In der in Figur 1 gezeigten Betriebsstellung wird durch den unteren Anschluss 24 ein Druckmedium zugeführt, das im Inneren des Zylinders 21 eine nicht dargestellte Druckfläche des Kolbens 22 von unten beaufschlagt und diesen mit dem Mahlboden 5 nach oben drückt, bis der Mahlboden 5 an einer Stufe 25 in Formschluss mit der Mahlwand 4 tritt. Indem in dieser, in Figur 1 gezeigten Betriebsstellung die Stufe 25 gegen eine untere Anfasung 26 der Mahlwand 4 tritt und ein oberhalb der Stufe 25 anschließender Bereich des Mahlbodens 5 passend in den von der Mahlwand 4 umschlossenen Querschnitt tritt, wird der Mahlraum 3 während des Mahlbetriebs entlang des Außenumfangs seines Mahlbodens abgedichtet. FIG. 1 shows in a cross section the upper portion of a vibrating mill 1 according to the invention according to a preferred embodiment. An overall view, partly schematic, shows FIG. 3 , This is a so-called disc vibratory mill. Theirs in FIG. 1 shown mowing unit 2 represents one of a separate, connected to the milling unit vibratory drive vibratable assembly which includes a grinding chamber 3, which is externally bounded by a cylindrical grinding wall 4. At this bottom side during the grinding operation includes a substantially circular grinding soil 5 at. On this are in the embodiment shown as Mahlelemente a Mahlring 6 and a millstone 7, which is a round, not cut in the illustration solid body, on. The outer diameter of the Mahlringes 6 is smaller than the inner diameter of the grinding wall 4, and the outer diameter of the grinding stone 7 is smaller than the inner diameter of the Mahlringes 6. The thus formed between the grinding wall 4 and Mahlring 6 Mahlspalt 8 and the Mahlspalt formed between Mahlring 6 and Mahlstein 7 9 allow a lateral relative movement of Mahlring 6 and millstone 7 both to each other and with respect to the grinding wall 4. At the latter includes sealed on the top side a Mahldeckel 10 at. In FIG. 1, in which the grinding base 5 is in its upper possible position during the so-called grinding phase, the vertical distance between the grinding base 5 and the grinding cover 10 is only slightly greater than the height of the grinding ring 6 and the grinding stone 7, so that just the desired Game for the lateral movement arises. To the grinding wall 4 includes radially outside a housing ring 11, which is bolted to the underside with a housing base 12 and thereby connected to a drive flange 13. On the upper side, the housing ring 11 is screwed to a housing cover 14. Its underside has a recess 15, in which edge a seal 16, in the example chosen an O-ring, and in a Mahldeckel 17 are used. The underside of the housing cover 14, the seal 16 and the grinding lid 17 are pressed against the upper end face of the grinding wall 4 by the clamping force of cover screws 18 distributed along the circumference. The housing cover 14 and the grinding lid 17 have off-center passage openings for forming an entry opening 19. Through this, the grinding stock (not shown) to be comminuted can be filled into the grinding chamber 3 from above, where it is distributed in the grinding gaps 8, 9. If, as described below, lateral oscillatory movements of the grinding elements 6, 7 occur, the grinding gaps 8, 9 locally change their width, whereby the material to be ground between the grinding elements 6, 7 and the grinding wall 4 is ground. The grinding wall 4, the grinding ring 6 and the grinding stone 7 may be made of a particularly suitable, in particular made of a hard material, while for the housing ring 11 and the other housing parts a conventional construction material, for example. Steel or light metal can be used. On the housing base 12, a bracket 20 is screwed on the underside, which carries with its free end a cylinder 21 shown in simplified form, whose upper side protruding piston 22 is fastened by screwing to the grinding base 5 on the underside. The cylinder 21 has two ports 23, 24 for supplying a pressurized fluid, such as air or hydraulic fluid. In the in FIG. 1 shown operating position is supplied through the lower port 24, a pressure medium, which acts in the interior of the cylinder 21, a pressure surface of the piston 22, not shown from below and presses it with the grinding soil 5 up until the grinding soil 5 at a stage 25 in positive engagement with the Grinding wall 4 occurs. By being in this, in FIG. 1 shown operating position, the stage 25 occurs against a lower chamfer 26 of the grinding wall 4 and a subsequent step 25 adjacent portion of the grinding tray 5 fits into the enclosed by the grinding wall 4 cross-section, the grinding chamber 3 is sealed during the grinding operation along the outer periphery of its grinding floor.

Figur 1 ist des weiteren zu entnehmen, dass die Mahleinheit 2 mit einer Kühleinrichtung zur rückseitigen, bzw. äußeren Kühlung der Mahlwand 4 ausgestattet ist. Diese umfasst im Beispiel zwei rückseitig an die Mahlwand 4 angrenzende Kühlnuten 47, die in die die Mahlwand 4 außen abstützende innere Wandoberfläche 48 des Gehäuseringes 11 eingebracht sind. Die oberen und unteren Kühlnuten 47, die sich in Umfangsrichtung von einem Zulauf 49 für ein Kühlmittel bis zu einem umfangsmäßig um etwa 10° beabstandeten, in der Zeichnung nicht dargestellten Ablauf für das Kühlmittel erstrecken, werden durch einen ebenfalls ringsegmentartigen Stützvorsprung 50 beabstandet, der im Bereich des Zu- und Ablaufes unterbrochen ist. Der Zu- und Ablauf sind in Umfangsrichtung durchflussmäßig getrennt, so dass ein gezielter Umlauf von Kühlmittel, welches bspw. auf eine gewünschte Temperatur geregelt werden kann, möglich ist. FIG. 1 Furthermore, it can be seen that the grinding unit 2 is equipped with a cooling device for the rear side or external cooling of the grinding wall 4. In the example, this comprises two cooling grooves 47 adjoining the grinding wall 4 at the back, which are introduced into the inner wall surface 48 of the casing ring 11 supporting the grinding wall 4 on the outside. The upper and lower cooling grooves 47, which extend in the circumferential direction from a coolant inlet 49 to a circumferentially spaced by about 10 °, not shown in the drawing flow for the coolant, are spaced by a likewise ring-segment-like support projection 50 which in Area of inlet and outlet is interrupted. The inlet and outlet are separated by flow in the circumferential direction, so that a targeted circulation of coolant, which can be regulated, for example, to a desired temperature, is possible.

Figur 2 zeigt vergleichsweise eine zweite Betriebsstellung, in welcher der obere Anschluss 23 mit einem Druckfluid beaufschlagt wird. Im Inneren des Zylinders 21 wird dadurch in nicht näher dargestellter Weise eine Druckangriffsfläche des Kolbens 22 von oben beaufschlagt, so dass der Kolben 22 den Mahlboden 5 nach unten zieht, bis dieser in einen definierten formschlüssigen Anschlag mit einem Bund 27 der Gehäusebasis 12 tritt. In der gezeigten, abgesenkten Betriebsstellung entsteht zwischen dem Mahlboden 5 und der Mahlwand 4 ein entlang des Umfangs verlaufender Spalt 28, durch welchen das beim Mahlen zerkleinerte Mahlgut zufolge der bei einer weiteren Schwingungsanregung auftretenden Fliehkräfte in einen ringförmigen Austragskanal 29 und darin ebenfalls zufolge Schwingungsanregung bis zu einer Austrittsöffnung 30 zu einem Auslass 31 gelangt. Im Querschnitt wird der Austragskanal 29 radial innen durch den Mahlboden 5, unterseitig durch eine sich daran federnd abstützende Dichtung 32 und die Gehäusebasis 12 und radial außen von der Gehäusebasis 12 begrenzt, während sich nach oben hin der Gehäusering 11 und die Mahlwand 4 anschließen. Der so gebildete Querschnitt des Austragskanals 29 liegt bezüglich des Mahlraumes schräg nach unten/radial außerhalb versetzt. FIG. 2 shows comparatively a second operating position in which the upper port 23 is acted upon by a pressurized fluid. In the interior of the cylinder 21, a pressure application surface of the piston 22 is acted upon from above in a manner not shown, so that the piston 22 pulls the grinding base 5 down until it enters a defined positive stop with a collar 27 of the housing base 12. In the illustrated, lowered operating position arises between the grinding floor 5 and the grinding wall 4, a circumferentially extending gap 28, through which the grinding material comminuted during grinding due to the centrifugal forces occurring in a further vibration excitation in an annular discharge channel 29 and also therein according to vibration excitation up to an outlet opening 30 to an outlet 31 passes. In cross-section, the discharge channel 29 is radially inwardly delimited by the grinding base 5, the underside by a resiliently supported thereon seal 32 and the housing base 12 and radially outside of the housing base 12, while at the top of the housing ring 11 and the grinding wall 4 connect. The thus formed cross-section of the discharge channel 29 is offset with respect to the grinding chamber obliquely downward / radially outside.

Figur 3 veranschaulicht schematisch, dass die in den Figuren 1 und 2 beschriebene Mahleinheit 2 der Schwingmühle 1 an dem Antriebsflansch 13 unterseitig mittels Feder-Dämpfer-Elementen 33 auf einem festen Untergrund abgestützt ist. An den Flansch 13, der oberseitig in eine Hülse 13' übergeht, ist unterseitig ein Schwingantrieb 34 mittels Schraubverbindungen angeflanscht. In dem gewählten Beispiel weist dieser einen Antriebsmotor 35, hier einen Elektromotor, auf, dessen Welle 36 in einem darüber befindlichen Gehäuse 37 eine zu der Welle 36 außermittige, an sich bekannte und daher zeichnerisch vereinfacht dargestellte Unwucht 40 dreht. Die auf diese Weise erzeugte Drehschwingung wird über den Antriebsflansch 13 auf die angeschlossene gesamte Mahleinheit 2, einschließlich aller am Mahlvorgang und am Austragsvorgang des Mahlgutes beteiligten Wandungen übertragen. FIG. 3 schematically illustrates that in the FIGS. 1 and 2 described grinding unit 2 of the vibratory mill 1 on the drive flange 13 is supported on the underside by means of spring-damper elements 33 on a solid surface. On the flange 13, which merges into a sleeve 13 'on the upper side, an oscillating drive 34 is flange-mounted on the underside by means of screw connections. In the example chosen, this has a drive motor 35, here an electric motor, on whose shaft 36 rotates in an overlying housing 37 to the shaft 36 off-center, known per se and therefore illustrated simplified unbalance 40. The torsional vibration generated in this way is transmitted via the drive flange 13 to the connected entire milling unit 2, including all involved in the grinding process and the discharge process of the ground material walls.

Weiterhin zeigt Figur 3 schematisch eine Steuerungseinrichtung 38, die Bestandteil von erfindungsgemäßen Drehzahländerungsmitteln 39 ist. Für den Mahl- bzw. für den Austragsbetrieb der Schwingmühle wird der Motor 35 von einer nicht mit dargestellten Einrichtung mit einer Betriebsspannung gespeist, der zunächst eine bestimmte Antriebsdrehzahl der Welle zugeordnet ist. In dem gewählten Beispiel ist die Steuerungseinrichtung 38 dazu geeignet, um mit in dem Gehäuse 37 angeordnete Stellmittel 41 in vorbestimmter, zeitlich veränderlicher Weise anzusteuern. In dem gewählten Beispiel handelt es sich bei den Stellmitteln 41 um eine an der exzentrischen Unwucht 40 von zwei gegenüberliegenden Seiten angreifende, schematisch angedeutete Bremse. An der Steuerung 38 kann mittels eines Bedienfelds 42 eine gewünschte Kennlinie vorgewählt werden, die entweder den zeitlichen Verlauf der Ansteuerung der Stellmittel 41 bestimmt oder eine Kennlinie, die sogleich einem gewünschten resultierenden Verlauf der resultierenden Antriebsdrehzahl über der Zeit entspricht.Further shows FIG. 3 schematically a control device 38, which is part of speed change means 39 according to the invention. For the grinding or for the discharge operation of the vibratory mill, the motor 35 is fed by a device not shown with an operating voltage, which is first assigned to a specific drive speed of the shaft. In the example chosen, the control device 38 is suitable for driving with adjusting means 41 arranged in the housing 37 in a predetermined, temporally variable manner. In the example chosen, the adjusting means 41 are a brake which acts on the eccentric unbalance 40 from two opposite sides and which is indicated schematically. On the controller 38, a desired characteristic can be preselected by means of a control panel 42, which determines either the time profile of the control of the actuating means 41 or a characteristic curve which immediately corresponds to a desired resulting curve of the resulting drive speed over time.

Die Ansteuerungssignale werden über eine Leitung 43 zu den Stellmitteln 41 übertragen und im Beispiel in geeigneter Form in eine korrespondierende, zeitlich veränderliche Druckkraft übersetzt, mit der die Bremskolben verzögernd gegen die Unwucht 40 treten. Mittels einer weiteren, gestrichelt dargestellten Signalleitung 44 (dies ist aber nicht notwendig der Fall) kann die Steuerung 38 auch mit dem Motor 35 direkt in Verbindung stehen, bspw. mittels einer Leitung, über die der Steuerung 38 ein Drehzahl-Signal zugeleitet wird. Ebenfalls lediglich beispielhaft, d. h. nicht notwendig, ist bei dem gezeigten Ausführungsbeispiel die Steuerung 38 dazu geeignet, um dem Bediener auf einem Display 45 unmittelbar einen aus den gewählten Einstellungen resultierenden auf die Mahleinheit einwirkenden Antriebsdrehzahl- Zeit-Verlauf 46 anzuzeigen, wobei die Antriebsdrehzahl U über der Zeit t aufgetragen ist. Aus Figur 3 wird in Verbindung mit den Figuren 1, 2 deutlich, dass die Drehebene der Unwucht 40 rechtwinklig bezüglich der senkrechten, den Mahlvorgang hauptsächlich bewirkenden Oberflächen von Mahlwand 4, Mahlring 6 und Mahlstein 7 sowie rechtwinklig bezüglich der seitlichen Berandungen des Austragskanals 29 angeordnet ist. Dies wirkt sich beim Durchfahren der Resonanzfrequenz vorteilhaft auf die Ablösung der Anhaftungen aus.The control signals are transmitted via a line 43 to the adjusting means 41 and translated in the example in a suitable form in a corresponding, time-varying compressive force with which the brake piston delaying the unbalance 40 occur. By means of a further, shown in dashed lines signal line 44 (but this is not necessarily the case), the controller 38 may also communicate with the motor 35 directly, for example. By means of a line through which the controller 38, a speed signal is fed. Also only by way of example, ie not necessary, in the embodiment shown, the controller 38 is adapted to the operator display on a display 45 directly from the selected settings resulting on the milling unit acting drive speed-time curve 46, wherein the drive speed U via the time t is applied. Out FIG. 3 will be in conjunction with the FIGS. 1 . 2 clearly that the rotational plane of the unbalance 40 is arranged at right angles with respect to the vertical, the grinding process mainly causing surfaces of the grinding wall 4, Mahlring 6 and millstone 7 and at right angles to the lateral boundaries of the discharge channel 29. This has an advantageous effect on the separation of the adhesions when passing through the resonance frequency.

Figuren 4a - 4c zeigen verschiedene Beispiele für bevorzugte Antriebsdrehzahl- Zeit-Verläufe 46. In dem Beispiel von Figur 4 a wird der Schwingantrieb zum Zeitpunkt t1 eingeschaltet, d. h. der Betrieb beginnt. Die aus der Motorspannung resultierende Antriebsdrehzahl Umax wird gleich zu Beginn zufolge der aktivierten Stellmittel 41 (Bremse) auf eine für den Mahlbetrieb gewünschte Grunddrehzahl Unenn abgesenkt. Nach der überwiegenden Dauer des Mahlbetriebs wird beginnend mit dem Zeitpunkt t2 bis t3 mittels der Steuerung 38 die Wirkung des Stellmittels 41 linear verringert, bis die wirksame Antriebsdrehzahl U der Maximaldrehzahl Umax entspricht. Dabei wird ein Drehzahlwert URes durchfahren, bei dem die Mahleinheit 2 zu Resonanzschwingungen angeregt wird. Von t3 bis t4 wird mittels der Steuerungseinrichtung 38 die Wirkung der Stellmittel 41 (Bremse) linear gesteigert, bis bei t4 wieder die Grund- bzw. Nenndrehzahl Unenn resultiert. Auch dabei wird die Resonanzdrehzahl URes kontrolliert durchfahren. Anschließend wird in dem Beispiel die Grunddrehzahl Unenn für ein weiteres Zeitintervall t4-t5 aufrecht erhalten und bei t5 der Mahlvorgang beendet. In dem gewählten Beispiel, jedoch nicht notwendig, beträgt die Grunddrehzahl Unenn bspw. ca. 800 bis 850 Umdrehungen je Minute (U/min), die Resonanzdrehzahl liegt bspw. im Bereich von 1000 -1100 U/min, und die erreichte Maximaldrehzahl Umax beträgt beispielsweise 1300 U/min. Im Beispiel von Figur 4a wird die Resonanzdrehzahl URes, nachdem der Mahlvorgang zum Zeitpunkt t2 bereits überwiegend durchgeführt wurde, zweimal in kontrollierter Weise, nämlich einmal aufwärts und einmal abwärts mit einer vorgewählten Steigung des Kurvenverlaufes, durchfahren. Da weder bei Unenn, noch bei Umax Resonanz in der Mahleinheit auftritt und URes beim Durchfahren nicht konstant gehalten wird, wird die Mahleinheit 2 jeweils nur kurzzeitig definiert in Resonanz versetzt, so dass keine Gefahr von Beschädigungen besteht. Alternativ wäre denkbar, die Resonanzdrehzahl für sehr kurze Zeitintervalle, in denen ebenfalls keine Beschädigung auftreten kann, konstant zu halten. FIGS. 4a-4c show various examples of preferred drive speed-time profiles 46. In the example of FIG. 4 a is the vibration drive at time t 1 is turned on, ie the operation begins. The resulting from the motor voltage input speed U max is equal to the beginning of the activated actuating means 41 (brake) lowered to a desired for the grinding operation base speed U nenn . After the overwhelming duration of the grinding operation, the effect of the actuating means 41 is linearly reduced starting from the time t 2 to t 3 by means of the controller 38 until the effective drive speed U corresponds to the maximum speed U max . In this case, a speed value U Res is passed, in which the grinding unit 2 is excited to resonant vibrations. From t 3 to t 4 , by means of the control device 38, the effect the adjusting means 41 (brake) increased linearly until at t 4 again the basic or rated speed U nom results. Also, the resonance speed U Res is passed through controlled. Subsequently, in the example, the basic rotational speed U nenn is maintained for a further time interval t 4 -t 5 and the grinding process is ended at t 5 . In the example chosen, but not necessary, the base speed U nenn example. Approximately 800 to 850 revolutions per minute (rpm), the resonance speed is, for example, in the range of 1000-1100 U / min, and reached the maximum speed U max is, for example, 1300 rpm. In the example of FIG. 4a is the resonance speed U Res , after the grinding process at time t 2 has already been carried out predominantly, twice in a controlled manner, namely once up and once down with a preselected slope of the curve, passed through. Since neither at U nenn , nor at U max resonance occurs in the milling unit and U Res is not kept constant when driving through, the milling unit 2 is only defined for a short time in resonance, so there is no risk of damage. Alternatively, it would be conceivable to keep the resonance speed constant for very short time intervals in which no damage can also occur.

Figur 4b zeigt ein zweites Ausführungsbeispiel, bei welchem die Resonanzdrehzahl bei insgesamt trapezartigem resultierendem Antriebsdrehzahl- Zeit-Verlauf 46 ebenfalls linear durchfahren wird. Im Unterschied zu Figur 4a sind während der Mahldauer t1 - t5 insgesamt zwei darin gleichmäßig verteilte Durchfahrungszyklen vorgesehen. Figur 4c zeigt ein drittes bevorzugtes Ausführungsbeispiel. Die Resonanzdrehzahl wird hier in drei Zyklen bei gerundetem Verlauf, ähnlich harmonischen Bereichen mit Unterbrechungen, durchfahren. FIG. 4b shows a second embodiment in which the resonance speed is also traversed linearly in total trapezoidal resulting drive speed-time course 46. In contrast to FIG. 4a are during the grinding time t 1 - t 5 a total of two evenly distributed Durchfahrungszyklen provided. Figure 4c shows a third preferred embodiment. The resonance speed is traversed here in three cycles with rounded course, similar to harmonic areas with interruptions.

Claims (15)

  1. Vibration mill, in particular a disk vibration mill, comprising a milling unit and a vibrating drive, by means of which the milling unit can be excited into vibrations depending on the drive rotational speed of the vibrating drive, wherein means (39) for changing the rotational speed are provided that are suitable for changing the drive rotational speed in a pre-definable, time-dependent manner during operation of the vibration mill (1),
    characterized in that
    the vibrating drive (34), by means of electrical and/or electronic circuits and/or electrical and/or electronic storage means contained in the means (39) for changing the drive rotational speed, is suitable for specifying at least one pre-defined drive rotational speed-time graph (46).
  2. Vibration mill according to Claim 1,
    characterized in that
    the vibrating drive (34) comprises a drive motor (35), in particular an electric motor, and at least one imbalance (40) which is driven, in particular rotationally driven, thereby.
  3. Vibration mill according to one or more of the previous claims,
    characterized in that
    the means (39) for changing the drive rotational speed comprise an open-loop control device (38) and/or a closed-loop control device for controlling actuators (41) for changing a drive rotational speed specified by the drive motor (35), and/or for controlling the drive motor (35).
  4. Vibration mill according to one or more of the previous claims,
    characterized in that
    starting from a predefined nominal speed (Unenn), the drive rotational speed-time graph (46) contains a single or multiple increase up to a maximum rotation speed (Umax), which is greater than or approximately equal to a resonant rotational speed (URes) at which the milling unit (2) is excited into resonant vibrations, that the drive rotational speed-time graph (46) comprises a holding phase of the maximum rotational speed (Umax) and that after an increase up to the maximum rotational speed (Umax), the drive rotational speed-time graph (46) exhibits a return to the nominal rotational speed (Unenn), and in particular a repeated holding phase of the nominal rotational speed (Unenn).
  5. Vibration mill according to one or more of the previous claims,
    characterized in that
    the drive rotational speed-time graph (46) comprises a cyclically recurring increase from the nominal speed (Unenn) to the maximum rotational speed (Umax).
  6. Vibration mill according to one or more of the previous claims,
    characterized in that
    in accordance with the drive rotational speed-time graph (46), a nominal rotational speed (Unenn) is assigned to each of a milling phase and a discharge phase and that in the milling phase and/or in the discharge phase at least one increase in the drive rotational speed from the nominal rotational speed (Unenn) up to a maximum rotational speed (Umax) is included.
  7. Vibration mill according to one or more of the previous claims,
    characterized in that
    the means (39) for changing the rotational speed comprise electrical, mechanical, electro-mechanical, pneumatic, hydraulic and/or magnetic, in particular electromagnetic, actuators (41) for changing the rotational speed.
  8. Vibration mill according to one or more of the previous claims,
    characterized in that
    the means (39) for changing the drive rotational speed vary the drive rotational speed and therefore also the vibration of the milling unit (2) in a linear and/or non-linear manner.
  9. Vibration mill according to one or more of the previous claims,
    characterized in that
    the vibration mill (1) comprises a cooling device, which in particular acts on the milling wall (4) surrounding the milling chamber (3).
  10. Method for operating a vibration mill, in particular a disk-vibration mill, which comprises a milling unit and a vibrating drive, wherein the milling unit is excited by the vibrating drive into vibrations dependent on the drive rotational speed thereof, wherein the drive rotational speed is changed in a predefined way during the operation of the vibration mill (1), wherein the drive rotational speed is changed according to a pre-defined drive rotational speed-time graph (46),
    characterized in that
    a vibrating mill is used,
    comprising means (39) for changing the drive rotational speed, and the vibrating drive (34) thereof, by means of electrical and/or electronic circuits and/or electrical and/or electronic storage means contained in the means (39) for changing the drive rotational speed, is suitable for specifying at least one predefined drive rotational speed-time graph (46), and wherein the drive rotational speed-time graph is defined by said circuits and/or storage means.
  11. Method according to claim 10,
    characterized in that
    starting from a predefined nominal rotational speed (Unenn), the drive rotational speed-time graph increases once or multiple times up to a maximum rotational speed (Umax), which is greater than or approximately equal to a resonant rotational speed (URes) at which the milling unit (2) is excited into resonant vibrations, that the drive rotational speed is held at the level of the maximum rotational speed (Umax) for a time interval
    and that after an increase up to the maximum rotational speed the drive rotational speed again is lowered again to the nominal rotational speed (Unenn) and in particular is held at the nominal rotational speed (Unenn) for a further time interval.
  12. Method according to one or more of claims 10-11,
    characterized in that
    the drive rotational speed is raised from the nominal rotational speed (Unenn) up to the maximum rotational speed (Umax) and lowered down to the nominal rotational speed (Unenn) again over multiple cycles.
  13. Method according to one or more of claims 10-12,
    characterized in that
    in a milling phase and/or in a discharge phase the drive rotational speed is increased from an assigned nominal rotational speed (Unenn) up to a maximum rotational speed (Umax), which is greater than or equal to the resonant rotational speed (URes).
  14. Method according to one or more of claims 10-13,
    characterized in that
    to change the rotational speed, electrical, mechanical, electromechanical, pneumatic, hydraulic and/or magnetic, in particular electromagnetic, actuators (41) are used.
  15. Method according to one or more of claims 10-14,
    characterized in that
    the drive rotational speed, and therefore also the vibration of the milling unit (2), is changed in a linear and/or non-linear manner.
EP07803119.2A 2006-09-08 2007-08-31 Vibration mill and method for the operation of a vibration mill Active EP2063992B1 (en)

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DE102006042823A DE102006042823A1 (en) 2006-09-08 2006-09-08 Vibratory mill and method for operating a vibratory mill
PCT/EP2007/059128 WO2008028870A1 (en) 2006-09-08 2007-08-31 Vibration mill and method for the operation of a vibration mill

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DE102019207224A1 (en) * 2019-05-17 2020-11-19 Thyssenkrupp Ag Device for comminuting feedstock and use of a cooling housing on the device
WO2020234062A1 (en) 2019-05-17 2020-11-26 Thyssenkrupp Industrial Solutions Ag Device for comminuting feed material, and use of a cooling housing on the device

Also Published As

Publication number Publication date
CN101534950A (en) 2009-09-16
DE102006042823A1 (en) 2008-03-27
WO2008028870A1 (en) 2008-03-13
CN101534950B (en) 2013-02-06
EP2063992A1 (en) 2009-06-03

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