LABORATORY VIBRATORY MILL

Abstract

The invention illustrates and describes a laboratory vibratory mill with at least one milling beaker holder which is mounted so as to be capable of oscillating, for at least one milling beaker, and with a temperature control device for controlling the temperature of the milling beaker by feeding in and/or carrying away a liquid or gaseous temperature control medium via at least one temperature control line to the milling beaker holder. According to the invention there is provision that the milling beaker holder has at least one heat transfer element which is connected to the temperature control line, wherein the heat transfer element has at least one medium duct for feeding through the temperature control medium, and wherein the temperature control of a milling beaker which is secured to and/or in the milling beaker holder is carried out by transferring heat between the temperature control medium conducted in the medium duct and the milling beaker via a wall of the heat transfer element.

Claims

1-10. (canceled)

11. A laboratory oscillation mill comprising: at least one swingingly mounted grinding bowl holder for at least one grinding bowl; and a tempering device for tempering the grinding bowl by supplying and/or discharging a liquid or gaseous tempering medium via at least one tempering line to the grinding bowl holder; wherein the grinding bowl holder has at least one heat transfer element connected to the tempering line; wherein the heat transfer element has at least one medium channel for passing through the tempering medium; wherein the tempering of the grinding bowl held on and/or in the grinding bowl holder is effected by heat transfer between the tempering medium guided in the medium channel and the grinding bowl via a wall of the heat transfer element; and wherein the heat transfer element is designed as a flat tempering plate, so that the grinding bowl can be placed with a bottom surface on the tempering plate.

12. The laboratory oscillation mill according to claim 1, wherein the grinding bowl holder is designed for tempering the grinding bowl without contact with the tempering medium.

13. The laboratory oscillation mill according to claim 1, wherein the tempering is affected by heat transfer between the tempering medium and the grinding bowl via contact surfaces of the heat transfer element and of the grinding bowl, which preferably lie directly against one another.

14. The laboratory oscillation mill according to claim 13, wherein the heat transfer element and the grinding bowl bear against one another over substantially the entire surface in the region of their contact surfaces.

15. The laboratory oscillation mill according to claim 13, wherein the heat transfer between the heat transfer element and the grinding bowl takes place substantially exclusively by heat conduction via the contact surfaces of the heat transfer element and the grinding bowl.

16. The laboratory oscillation mill according to claim 1, wherein the grinding bowl holder is designed to brace the grinding bowl against the heat transfer element.

17. The laboratory oscillation mill according to claim 1, wherein a measuring, control and/or regulating device is provided for preferably automatically controlling and/or regulating the temperature of the grinding bowl holder and/or of the grinding bowl and/or the temperature in a grinding chamber of the grinding bowl.

18. The laboratory oscillation mill according to claim 17, wherein at least two grinding bowl holders are provided; and wherein the measuring, control and/or regulating device is designed for controlling and/or regulating the temperatures at the grinding bowl holders and/or in and/or on the grinding bowls independently of one another.

19. A method for tempering a grinding bowl during a grinding process in a laboratory oscillation mill according to claim 1, wherein at least one temperature at the grinding bowl holder and/or in and/or at the grinding bowl and/or at and/or in a tempering line for a tempering medium for tempering the grinding bowl holder and/or the grinding bowl is measured and controlled and/or regulated.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawing shows examples of embodiments of the invention, which are described below. They show.

[0030] FIG. 1 is a perspective view of a laboratory vibrating mill according to the invention,

[0031] FIG. 2 is a top view of the laboratory mill from FIG. 1,

[0032] FIG. 3 is a view of the laboratory mill from FIG. 1 from below,

[0033] FIG. 4 is an enlarged partial view of the right grinding bowl holder of the laboratory vibrating mill shown in FIG. 3,

[0034] FIG. 5 is the perspective view of the grinding bowl holder from FIG. 4, wherein the grinding bowl holder has a two-part plate-shaped heat transfer element and an external part of the heat transfer element is hidden on the connection side of the heat transfer element,

[0035] FIG. 6 is a single perspective view of the two-part heat transfer element of the grinding bowl holders shown enlarged in FIGS. 4 and 5,

[0036] FIG. 7 is a perspective view of the grinding bowl holder shown in FIG. 2 on the right in a top view, before inserting a grinding bowl into the grinding bowl holder,

[0037] FIG. 8 is a schematic process diagram of a first embodiment of a process according to the invention for tempering grinding bowls in a vibrating mill and

[0038] FIG. 9 is a schematic process diagram of an alternative embodiment of a process for tempering the grinding bowls in a vibrating mill.

DETAILED DESCRIPTION

[0039] FIG. 1 shows a top view of a vibrating mill 1 for two grinding bowls 2, 3 performing circular arc-shaped vibrations in a horizontal position. A pendulum drive of the vibrating mill 1 is constructed in several parts with an eccentric shaft 4 mounted to rotate about a vertical eccentric axis and with two swinging arms 5, 6 each mounted to swing about vertical swinging axes and connected to the eccentric shaft 4 via couplings. Grinding bowl holders 7, 8 for the grinding bowls 2, 3 are attached to the swinging arms 5, 6. Furthermore, a motor unit 10 coupled to the eccentric shaft 4 via a V-belt 9 is provided for torque transmission. The eccentric shaft 4 is rotatably mounted on a base plate 11. Furthermore, two bearing bolts 12, 13 are attached to the base plate 11, around which the swing arms 5, 6 are rotatably mounted. Finally, the motor unit 10 is arranged on the base plate 11. The eccentric shaft 4, the bearing bolts 12, 13 and the motor unit 10 thus form, together with the base plate 11, a constructional unit which can stand on a floor or ground via damping elements.

[0040] The motor unit 10 transmits a torque to the eccentric shaft 4 via the V-belt 9. A rotary movement of the eccentric shaft 4 is converted via the couplings into an oscillating movement of the oscillators 5, 6. The oscillation frequency can be between 3 and 50 Hz, preferably up to 35 Hz. The oscillation path (double amplitude deflection) of the grinding bowl can be between 20 and 50 mm, preferably between 20 and 30 mm.

[0041] Temperature control, i.e. cooling or heating, of the grinding bowls 2, 3 is possible via a temperature control device not shown in detail. To transport a tempering medium, which can be liquid or gaseous, from a stationary part 14, 15 of the vibrating mill 1 to a grinding bowl holder 7, 8 and to discharge the medium from the respective grinding bowl holder 7, 8 to the stationary part 14, 15, each grinding bowl holder 7, 8 is connected to two tempering lines 16, 17. One of the two temperature control lines 16, 17 is provided for the supply, the other of the two temperature control lines 16, 17 for the discharge of a gas or liquid temperature control medium, in particular liquid nitrogen, to the respective grinding bowl holder 7, 8.

[0042] The temperature control lines 16, 17 are preferably designed as continuous uninterrupted pipelines. The temperature control lines 16, 17 can, for example, be made of stainless steel or plastic or have stainless steel and/or plastic.

[0043] The structure of the cable routing is the same for both grinding bowl holders 7, 8, so that only one cable routing is described below as an example. In this case, the line arrangement with the temperature control lines 16, 17 of a grinding bowl holder 7 is designed mirror-symmetrically to the line routing of the second grinding bowl holder 8.

[0044] To compensate for relative movements that occur between a grinding bowl holder 7, 8 and the stationary part 14, 15 assigned via the tempering lines 16, 17 during operation of the vibrating mill 1, each line 16, 17 has a compensating element 18, 19. Each line 16, 17 is designed as a rigid pipeline over its entire length, with the compensating element 18, 19 being formed by a pipeline section of the line 16, 17.

[0045] During operation of the vibrating mill 1, the relative movements cause an oscillating deformation of the pipe sections forming the compensating elements 18, 19, whereby the pipe sections of the respective pipe 16, 17 adjacent to the compensating elements 18, 19 are comparatively less deformed. The design of the compensating elements 18, 19 as rigid pipeline sections enables the compensation of relative movements without having to use pipeline parts that are connected to each other so that they can rotate and/or swivel relative to each other. In particular, it is not necessary to use the rotary unions known from the prior art to compensate for relative movements, so that a hermetically sealed, uninterrupted connection and a permanently leak-free transport of the tempering medium between the grinding bowl holders 7, 8 and the stationary parts 14, 15 is guaranteed in a simple manner. In particular, it is not necessary to use sealing elements to compensate for relative movements, as is the case with rotary unions.

[0046] For the connection of the temperature control lines 16, 17 to the grinding bowl holders 7, 8 on the one hand and for the connection to the stationary parts 14, 15 on the other hand, connection and accessory parts of the assembly technology known per se from the state of the art can be provided. The connection of the temperature control lines as such, i.e. decoupled from the compensation of relative movements, can be made via sealing means in order to enable a sealing connection between the respective line 16, 17 and the grinding bowl holder 7, 8 on the one hand and the stationary part 14, 15 on the other hand.

[0047] In FIGS. 4 and 5 the grinding bowl holder 7 is shown enlarged in the view according to FIG. 3. It is not shown that a temperature control device is provided for controlling the temperature of the grinding bowl 2 by supplying and/or discharging a liquid or gaseous temperature control medium via the temperature control lines 16, 17 to the grinding bowl holder 7, 8. In the simplest case, the temperature control device has a conveying means for the temperature control medium and a container for holding a temperature control medium. A closed circuit of the temperature control medium via the temperature control line 16, 17 is also preferably provided.

[0048] Each grinding bowl holder 7, 8 has a heat transfer element 20 connected to the temperature control lines 16, 17, which in the embodiment shown is plate-shaped and has an inner first plate part 21 and an outer second plate part 22 on the connection side of the heat transfer element 20. The temperature control lines 16, 17 are connected on the outside of the outer plate part 22 to the plate part 22 by means of connecting elements known per se from the prior art.

[0049] FIG. 5 shows the grinding bowl holder 7 from FIG. 4, with the outer plate part 22 hidden. This allows a clear view of the inner plate part 21, in which a media channel 23 is formed for the temperature control medium to flow through. By joining the plate parts 21, 22, which can be done by welding or gluing, the media channel 23 is hermetically sealed from the environment. It is also possible to screw the plate parts 21, 22 together.

[0050] During the tempering of a grinding bowl 2, 3, i.e. during the passage of a cold or warm or hot tempering medium through the tempering lines 16, 17, heat is transferred between the tempering medium guided in the medium channel 23 and the grinding bowl 2 via a wall of the heat transfer element 20, in the present case via the inner plate part 21. By guiding the tempering medium in the medium channel 23, tempering of the grinding bowl 2, 3 is possible in which the latter does not come into contact with the tempering medium or in which any contact and thus the risk of contamination of the grinding bowl 2, 3 with the tempering medium is excluded. The media channel 23 is meander-shaped and opens into two blind holes 23a, 23b. In addition, ring milled holes 23c are provided to improve heat transfer.

[0051] The heat transfer between the tempering medium and the grinding bowl 2, 3 takes place via metallic contact surfaces of the heat transfer element 10 and the grinding bowl 2 that lie against each other, whereby in FIG. 7 the grinding bowl holder 8 from FIG. 2 is shown after the grinding bowl 3 has been removed. As can be seen from FIG. 7, a flat contact surface 24 is provided on the upper side or the outer side of the plate part 21 facing the grinding bowl 2, which contact surface rests against an outer bottom surface of the grinding bowl 2 over substantially the entire area during the grinding process. In the embodiment shown, heat is transferred between the heat transfer element 20 and the grinding bowl 2 exclusively by heat conduction via the contact surface 24 of the plate part 21 and the bottom surface of the grinding bowl 2.

[0052] The grinding bowl holder 7, 8 of the laboratory mill 1 shown has in each case a holding bracket 25 firmly connected to a rocker 5, 6, which cooperates with a horizontally adjustable further holding bracket 26. By adjusting the clamping screw 27, the outer retaining bracket 26 can be clamped against the inner retaining bracket 25 and thus a grinding bowl 2, 3 can be clamped horizontally between the retaining brackets 25, 26.

[0053] Clamping pieces 28 arranged in the corner areas are provided on the outer retaining bracket 26, which, when the grinding bowl 2, 3 is clamped horizontally in the grinding bowl holder 7, 8, cause the grinding bowl 2, 3 to be automatically pressed downwards against the inner plate part 21 of the heat transfer element 20 by force deflection. For this purpose, the clamping pieces 28 can be chamfered on the inner side facing the plate part 21 or have a corresponding clamping slope.

[0054] In the immediate vicinity of the grinding bowl, namely on each heat transfer element 20, there are preferably two temperature sensors 29 for measuring temperature on the heat transfer element 20. The temperature sensors 29 are connected via electrical lines not shown to an evaluation unit of a measuring, control and/or regulating device not shown for automatically regulating the temperature of the grinding bowl holder 6, 7. The temperature sensors 29 can be provided here for measuring the temperature of a plate part 21, 22 and/or can also engage into the area of the medium channel 23 via holes in the outer plate part 22 of the heat transfer element 20, so that a measuring sensor of the respective temperature sensor 29 engages in the temperature control medium guided in the interior of the medium channel 23 or is flushed around by the temperature control medium. This makes it possible to also directly measure the temperature of the temperature control medium in the area of the grinding bowl holder 6, 7. Due to the arrangement of the temperature sensors 29 in local proximity to the grinding bowl 2, 3, a temperature control of the temperatures at and/or in the grinding bowls 2, 3 is possible with low control inertia, so that a high precision and high speed of the temperature control can be achieved.

[0055] In a non-shown embodiment of a vibrating mill 1, a temperature sensor 29 is provided for each heat transfer element 20. The temperature sensors 29 are connected via electrical lines, which are not shown, to an evaluation unit of a measuring and/or control device 30, which is not shown, for automatic control of the temperature of the grinding bowl holder 6, 7.

[0056] FIGS. 8 and 9 schematically show two alternative methods for controlling the temperature of two grinding bowls 2, 3 of a laboratory vibrating mill 1, which is not shown in detail. A measuring, control and/or regulating device 30 is provided for automatically regulating the temperature of two grinding bowl holders 7, 8 of the vibrating mill 1. The temperature control is carried out with the aid of at least two temperature sensors 29, with which the temperatures of two heat transfer elements 20 of the grinding bowl holders 7, 8 are determined during the operation of the vibrating mill 1 or during a grinding process. During the grinding process, the grinding bowls 2, 3 stand on the heat transfer element 20. The heat transfer preferably takes place exclusively by heat conduction via contacting surfaces.

[0057] For the supply and discharge of a liquid or gaseous tempering medium, in the embodiment examples of liquid nitrogen, to the heat transfer elements 20 or to the respective grinding bowl holder 7, 8, each grinding bowl holder 7, 8 is connected to two tempering lines 16, 17. The temperature control lines 16, 17 of a grinding bowl holder 7, 8 are connected to a rotary feedthrough 31 to enable the compensation of relative movements between the vibrating grinding bowl 2, 3 and a stationary part of the laboratory mill 1.

[0058] Each rotary union 31 is connected to a supply line 32 and to a discharge line 33 for supplying the temperature control medium from a medium container 34, for example a nitrogen tank, or for discharging the temperature control medium after it has flowed through the heat exchanger element 20 into a disposal device for the temperature control medium, in the present case a pressure relief pipe 35. Further temperature sensors 36 are provided for measuring the temperature of the medium in the discharge pipes 33. The further temperature sensors 36 serve in particular for error handling. With a measured value associated with each discharge line 33, leakage can be concluded for each discharge line 33 and associated heat transfer element 20 as well as the associated lines 32 and rotary unions 31. In this way, proper operation can be efficiently monitored via measured values without having to physically check the lines. Finally, the lines are routed to the expansion pipe 35 via a choke 37.

[0059] In a not shown and preferred embodiment, it is intended to combine the discharge lines 33 in order to lead them via a throttle 37 to the expansion pipe 35. In this embodiment, a temperature measurement with at least one sensor 36 is provided after the merging.

[0060] The supply of the tempering medium from the medium container 34 via the supply lines 32 to the respective rotary union 31 is effected with a solenoid valve 38 as an actuator of a closed control loop depending on the temperatures determined at the grinding bowl holders 7, 8 via the temperature sensors 29. The solenoid valve 38 is thus provided to effect the clocked addition or feeding of the temperature control medium into the supply lines 32 to the two grinding bowl holders 7, 8. The medium supply temperature can be determined by means of a further temperature sensor 39.

[0061] Furthermore, the measuring, control and/or regulating device 30 has an evaluation or computer unit, which is not shown, with which a comparison of the measured temperatures with predefined setpoint values is carried out, whereby the actuator of the control circuit is subsequently actuated on the basis of the setpoint/actual value comparison. In the embodiment example shown, the timing of the solenoid valve 38 is changed accordingly depending on the setpoint/actual value comparison.

[0062] It is understood that the process sequence described in FIG. 8 for tempering the grinding bowls 2, 3 via the tempering of the grinding bowl holders 7, 8 can also be provided in a corresponding manner when using other tempering media. In addition, the control method described also allows the temperature of the grinding bowls 2, 3 to be determined and controlled directly. For this purpose, temperature sensors can be arranged on and/or in the grinding bowls 2, 3.

[0063] The data transmission between the sensors and an evaluation device of the measuring, control and/or regulating device can take place wired or wirelessly, for example via radio.

[0064] FIG. 9 schematically shows the process sequence for an alternative method of tempering the grinding bowls 2, 3. In contrast to the process sequence shown in FIG. 8 and described above, two solenoid valves 38 are provided according to FIG. 9 in order to adjust the timing of the respective solenoid valve 38 depending on the temperature measured at the respective grinding bowl holder 7, 8. This makes it possible to cool or heat the grinding bowls 2, 3 to different degrees and to control the temperatures in and/or on the grinding bowls independently of each other.

LIST OF REFERENCE SIGNS

[0065] 1 Vibrating Mill [0066] 2 Grinding bowl [0067] 3 Grinding bowl [0068] 4 Eccentric shaft [0069] 5 Swing arm [0070] 6 Swing arm [0071] 7 Grinding bowl holder [0072] 8 Grinding bowl holder [0073] 9 V-belt [0074] 10 Motor unit [0075] 11 Base plate [0076] 12 Bearing bolt [0077] 13 Bearing bolt [0078] 14 stationary part [0079] 15 stationary part [0080] 16 Temperature control line [0081] 17 Temperature control line [0082] 18 Compensating element [0083] 19 Compensating element [0084] 20 Heat transfer element [0085] 21 Plate part [0086] 22 Plate part [0087] 23 Media channel [0088] 23a Blind hole [0089] 23b Blind hole [0090] 23c Ring milling [0091] 24 Contact surface [0092] 25 Retaining bracket [0093] 26 Retaining bracket [0094] 27 Clamping screw [0095] 28 Clamping piece [0096] 29 Sensor [0097] 30 Measuring, control and/or regulating device [0098] 31 Rotary union [0099] 32 Feed line [0100] 33 Derivation [0101] 34 Media container [0102] 35 Expansion tube [0103] 36 Sensor [0104] 37 Choke [0105] 38 Solenoid valve [0106] 39 Sensor