DE102018113751A1 - Cutting mill for the cutting crushing of samples - Google Patents

Abstract

The invention relates to a cutting mill (10) for cutting specimens, comprising: a tool housing (12), a drive motor (14) and a drive shaft (42), a grinding chamber (16) having a cutting rotor (38) disposed therein for cutting the samples in the grinding chamber (16), wherein the cutting rotor (38) defines an axis of rotation (A) and the grinding chamber (16) on the motor side axially bounded by a Mahlkammerrückwand (24), wherein the Mahlkammerrückwand (24) has a shaft passage opening (28) through which the cutting rotor (38) of the drive shaft (42) can be driven, wherein the shaft passage opening (28) in the Mahlkammerrückwand (24) by a labyrinth seal (60) is sealed.

Description

Field of the invention

The invention relates to a cutting mill for the cutting crushing of samples, in particular on a laboratory scale with a rotating about a horizontal axis cutting rotor.

Background of the invention

Cutting mills crush the samples by a scissors-type cutting effect, typically between a rotating cutting rotor having one or more substantially axially extending cutting edges and one or more stationary counter-cutting edges also extending substantially axially. Such laboratory granulators are particularly suitable for the comminution of tough or fibrous samples, e.g. biological samples such as straw but e.g. also plastic films, just to name a few examples. Examples of such laboratory granulators are e.g. Pulverisette @ 19 and Pulverisette @ 25 of the Applicant, the basic construction of which is hereby incorporated by reference. Corresponding product descriptions of Pulverisette @ 19 and Pulverisette @ 25 can be found e.g. at www.fritsch.de.

In the case of these granulators, more or less free-flowing bulk material is typically filled into the grinding chamber via a filling funnel in which the cutting rotor rotates horizontally. The cutting rotor may have different geometries, e.g. So-called V-cutting, which has a twist and thus a good cutting action especially for the comminution of tough-elastic materials and films. From this it is clear that the definition of a substantially axially extending cutting edge is not limited to that the cutting edge runs strictly parallel to the axis of rotation, but also to include oblique cutting edges with an axis-parallel component. The substantially axially extending cutting edges can therefore also run obliquely to the axis of rotation, which corresponds in principle to a helix. Below the cutting rotor is typically a sieve, e.g. a screen cassette through which that sample material which has already been sufficiently crushed, can trickle through to be collected in an underlying collecting vessel. With regard to further design details, which are generally known to the person skilled in the art, reference is made to the product descriptions of the granulators Pulverisette® 19 and Pulverisette® 25 of the Applicant, which can be downloaded at the time of the application and its disclosure under www.fritsch.de, and which are incorporated herein by reference with respect to the basic construction of such a cutting mill.

In such a cutting mill, the torque from the motor shaft to a rotor seat, e.g. transmitted by a feather key. This rotor mount was typically permanently installed in previous granulators and could only be removed from the device with extensive disassembly of the device. The seal of the rotor mount was done in these laboratory granulators typically using felt rings.

Although the use of a separate rotor mount allows a simple manual insertion of the cutting rotor on the rotor mount, however, the torque transmission is accomplished in some previously known granulators relatively far outward on driving pins, which in turn has led to that was sealed to a relatively large diameter. Relative to a predefined speed, a large diameter of the gasket means a relatively high peripheral speed at the gasket, which in turn is accompanied by a relatively large amount of heat. Furthermore, in previous cutting mills, the rotor mount was typically not easily removed for cleaning. In addition, the felt rings used were also not easy to replace easily. Moreover, although the gasket has basically been tried and tested by means of the felt rings, e.g. Waxes, oils or resins get to the seal and may affect the sealing effect.

These felt seals have nevertheless proven themselves in principle and have therefore been used for decades. Nonetheless, the sealing concept of a granulator can be improved. In particular, the accessibility of the seal can be further improved.

General description of the invention

It is therefore an object of the invention to provide a cutting mill of the type mentioned, which is easy to maintain and / or which can be cleaned well, especially in the field of Mahlkammerrückwand and the drive shaft.

Another aspect of the object of the invention is to provide a granulator which, in the region of the drive shaft, despite a possibly high peripheral speed at sealing points, has a low heat development.

A further aspect of the object of the invention is to provide a cutting mill which has a good sealing effect between the grinding chamber and the area of the drive motor.

Another aspect of the object of the invention is to provide a granulator which allows improved access to the seal of the drive shaft in the grinding chamber rear wall.

The object of the invention is solved by the subject matter of the independent claims. Advantageous developments of the invention are the subject of the dependent claims.

The invention relates to a cutting mill for the cutting crushing of samples, in particular on a laboratory scale. Such cutting mills for the cutting crushing of samples work according to the scissors principle. The cutting edges of the cutting rotor and the counter-blades extend substantially axially and radially offset from the axis of rotation of the cutting rotor. The grinding chamber thus preferably has circumferentially axially offset and substantially axially extending counter knife, which cooperate with the cutting blades of the cutting rotor, so that the samples between the cutting blades of the cutting rotor and the counter blades are cut according to the scissors principle, if the cutting edges of the cutting rotor and the stationary Sliding past each other.

In this case, should not be limited essentially limited to cutting axially extending substantially parallel to the axis of rotation. On the contrary, the cutters can in particular also be inclined, e.g. run along a helix or have twist. For example, For example, cutting rotors can be used with so-called V-cutting edges, in which the cutting edges, although axially offset from the axis of rotation and substantially axially but obliquely along a helix, so that the cutting edges have a twist. Such laboratory granulators are generally known to the person skilled in the art, cf. e.g. www.fritsch.de.

The granulator includes
a device housing,
a drive motor arranged in particular in the device housing and a drive shaft which may have the motor shaft and possibly further shaft elements such as a rotor receiving element mounted on the motor shaft,
a grinding chamber with a cutting rotor disposed therein for cutting the samples in the grinding chamber.

The cutting rotor rotatably driven by the drive shaft rotates about an axis of rotation within the grinding chamber. The grinding chamber is motor-side axially, i. axially with respect to the axis of rotation or motor-front side, bounded by a Mahlkammerrückwand. The cutting rotor is preferably cylindrical on the whole and the motor-side end face of the cylindrical cutting rotor is parallel to the Mahlkammerrückwand. The grinding chamber rear wall has a shaft passage opening, through which the cutting rotor can be driven by the drive shaft. In particular, the drive shaft extends through the shaft passage opening in order to drive the cutting rotor in the grinding chamber in rotation. Preferably, the drive shaft and / or the axis of rotation of the cutting rotor run horizontally and / or the grinding chamber back wall vertically.

Unlike earlier granulators, the shaft passage opening in the grinding chamber rear wall is now sealed by means of a labyrinth seal. Labyrinth seals are sometimes referred to as gap seals because they are a non-contact shaft seal. The sealing effect is based on the extension of the flow path through the sealing gap, whereby the flow resistance is increased. This path extension may e.g. be achieved by an intermeshing of elements of the rotor and stator, a so-called intermeshing.

The speed of rotation of the cutting rotor at the cutting mill may be e.g. in the interval from 20 U / min to 5000 U / min, preferably between 50 and 3000 U / min. It has now been found that with some cutting mills the radius or circumference of the seals on the grinding chamber rear wall is relatively large by design, which causes a relatively high peripheral speed at the seal. The use of a labyrinth seal is advantageous, among other things, since it can reduce the heat generation at the grinding chamber rear wall.

Another advantage of using a labyrinth seal at this point is that improved access to the area inside and behind the shaft passage opening in the grinding chamber rear wall can be made possible, so that the cutting mill is easy to maintain and in particular simplifies cleaning in the area of the shaft passage opening in the grinding chamber rear wall and can be improved. This can e.g. be helpful when crushing oily or resinous samples, as this could possibly lead in conventional cutting mills that when crushing the samples oil and / or resinous residues could diffuse into the region of the seal of the shaft passage opening.

Another advantage of using a labyrinth seal is longevity and ease of maintenance. Furthermore, the labyrinth seal can be easily installed and removed, e.g. to clean, control and / or replace them.

The grinding chamber of the granulator has at least partially, preferably at least below, a peripheral sieve wall, which separates the grinding chamber from a collecting container, such that the sieve wall such sample particles which were crushed under a predefined by the sieve openings particle size, directly in the cutting crushing of the samples through the screen openings in the collecting container.

Preferably, the sieve wall is formed as part of a sieve cassette, wherein the sieve cassette is insertable as a unit below the cutting rotor in the grinding chamber.

More preferably, the device housing comprises an axially with respect to the axis of rotation end cap. The closure lid is arranged on the side of the grinding chamber opposite the grinding chamber rear wall and can be opened in order to open the grinding chamber. When the grinding chamber is open, the cutting rotor and / or optionally other parts such as the sieve cassette and / or the labyrinth seal can be removed from the grinding chamber. This allows the parts to be exchanged, e.g. against another cutting rotor and / or another screen cassette.

The cutting rotor is placed on the one hand on the drive shaft and thus mounted on the motor side via the drive shaft, and on the other hand preferably on the motor or the labyrinth seal opposite side in the openable cap when the cap is closed. For this purpose, the closure cap may be a e.g. comprise cone-shaped abutment. This construction allows for easy expandability of the components, e.g. for cleaning and replacement.

The cutting rotor is preferably coaxial or concentric by hand on the drive shaft attachable and removable when the cap or the grinding chamber is open. When opening the cap, the anvil is opened and the cutting rotor can then be manually removed from the drive shaft. The cutting rotor is for this purpose e.g. only attached to the drive axle.

The torque is preferably transmitted by a positive coupling of the drive shaft to the cutting rotor when the grinding chamber is closed. For this, e.g. Includes driver elements which positively engage in the cutting rotor when the cutting rotor is mounted on the drive shaft to transmit the torque by means of the driver elements on the cutting rotor.

According to a preferred embodiment of the invention, the drive shaft is designed in several parts and comprises at least one primary shaft, which may e.g. be directly the motor shaft, and a coaxially mounted on the primary shaft intermediate piece, the so-called rotor receiving element. The rotor-receiving element is then coaxially mounted on the primary shaft and coupling means are included between the primary shaft and the rotor-receiving element, which effect the transmission of torque from the primary shaft to the rotor-receiving element, e.g. a feather key. The cutting rotor is plugged onto the rotor receiving element and can be removed easily and without tools with the grinding chamber open by hand from the rotor receiving element. The rotor receiving element may also be withdrawn from the primary shaft, in which case a removal tool may be required, for example. a central screw for pushing the rotor receiving element of the primary shaft, wherein optionally parts of the labyrinth seal are automatically withdrawn from the Mahlkammerrückwand.

Further preferably, a Mitnehmerflansch is included, which extends around the drive shaft and has a substantially larger diameter than the motor shaft. The driver elements, e.g. Driving pins engage on the one hand in the Mitnehmerflansch and on the other hand in the cutting rotor to cause the torque transmission from the drive shaft to the cutting rotor at the largest possible radius.

The gap dimension of the labyrinth seal is preferably between 0.05 mm and 2 mm, more preferably between 0.1 mm and 0.5 mm, radially preferably in the range of 0.2 mm, axially possibly slightly more due to bearing play.

The driver elements are preferably designed as axially extending driving pins, wherein the radially outer boundary of at least 10 mm, preferably at least 15 mm, preferably at least 20 mm or preferably at least 25 mm, e.g. 31.5 mm radially away from the axis of rotation, whereby a high torque can be transmitted.

Preferably, the Mitnehmerflansch is formed as a part of the rotor receiving element and the rotor receiving element with the Mitnehmerflansch as a unit attachable to the primary shaft. This has proven itself for the transmission of the required torques in the cutting mill.

According to a preferred embodiment of the invention, the Mitnehmerflansch is at least partially disposed within the shaft passage opening. This has proven to be beneficial in terms of the size proved. For this purpose, although a relatively large shaft passage opening is required, but this is easy to handle with a labyrinth seal.

The labyrinth seal preferably comprises an inner labyrinth ring co-rotating with the drive shaft and a labyrinth ring cover with a milling chamber side, a mill chamber-side axial end face of the inner labyrinth ring being intermeshed with an axial end face of the mill chamber labyrinth ring cover.

Further preferably, the labyrinth seal comprises the inner labyrinth ring co-rotating with the drive shaft and an engine-side labyrinth ring cover, wherein an engine-side axial end surface of the inner labyrinth ring is interlocked with an axial end surface of the engine-side labyrinth ring cover.

Such an axially front-side concavity is advantageous with respect to the demotability of the labyrinth seal.

Preferably, the grinding chamber rear wall has a grinding chamber-side annular recess in which the mill chamber-side labyrinth ring cover is fixed. It is particularly advantageous if the grinding chamber-side end surface of the milling chamber-side labyrinth ring cover is flush with the grinding chamber rear wall.

The mill chamber-side labyrinth ring cover is preferably clamped in the mill chamber-side annular recess, so that when the cutting rotor is withdrawn from the drive shaft or the rotor receiving element, the labyrinth seal remains assembled. However, the inner labyrinth ring in the direction of the motor to the grinding chamber is basically removable, when the clamping of the grinding chamber side labyrinth ring cover is overcome in the mill chamber side annular recess and the mill chamber side labyrinth ring with the inner labyrinth ring is removed from the drive shaft. Preferably, for this purpose, the rotor receiving element is withdrawn by overcoming a certain clamping force from the primary shaft, thereby also the inner labyrinth ring and the mill chamber-side labyrinth ring cover are deducted from the drive shaft, e.g. supported on the motor side by the driver flange.

The grinding chamber-side labyrinth ring cover can be clamped in the grinding chamber rear wall or in the grinding chamber-side annular recess of the grinding chamber rear wall by means of a preferably positively inserted O-ring and be withdrawn by overcoming the clamping force caused thereby.

Preferably, the inner labyrinth ring is arranged radially on the outside of the rotor receiving element, in particular radially outward on the driver flange.

According to a further embodiment, an air flow generating device is provided, which generates an air flow through the gap of the labyrinth seal, preferably from the motor in the direction of the grinding chamber. Thereby, the effect of the labyrinth seal can be improved, to the extent that the diffusion of dirt from the grinding chamber in the direction of the engine area can be reduced by the shaft passage opening.

For this purpose, the inner labyrinth ring can have fan blades, which generate a flow of air through the gap of the labyrinth seal during rotation of the inner labyrinth ring. In this case, the large radius of the seal, which initially appears to be disadvantageous for the seal as such, proves to be advantageous, since the large circumferential speed associated therewith can have a positive effect on the generation of an airflow.

For example, the fan blades are expediently arranged on the radially outer circumferential wall of the inner labyrinth ring.

Preferably, an air supply to the ventilation duct is provided between the grinding chamber rear wall and the drive motor, e.g. in the motor side of the grinding chamber rear wall, through which the air flow is guided in the direction of the grinding chamber through the labyrinth seal.

Alternatively or additionally, a circumferential "open labyrinth" or so-called transparent labyrinth may be provided. The labyrinth seal in turn comprises an inner labyrinth ring co-rotating with the drive shaft and the shaft passage opening has an inner radial annular wall within which the inner labyrinth ring is disposed such that the inner radial annular wall annularly surrounds the inner labyrinth ring. The open labyrinth or translucent labyrinth is characterized in that either the inner radial annular wall or the outer radial annular wall of the inner labyrinth ring defines a meandering shape in axial cross section, but the inner radial annular wall and the outer radial annular wall of the inner labyrinth ring are not intermeshed such that the inner labyrinth ring can nevertheless be withdrawn axially from the shaft passage opening.

Preferably, the meandering shape of the open labyrinth or translucent labyrinth in the axial cross-section is radially tapering, for example, triangular in axial cross-section, possibly triangular tapered.

Experiments have shown that such an open labyrinth or translucent labyrinth or geometries can create vortices that can cause air pockets and thus make it difficult for dirt to pass through the labyrinth seal.

In the following the invention will be explained in more detail by means of embodiments and with reference to the figures, wherein the same and similar elements are partially provided with the same reference numerals and the features of the various embodiments can be combined.

list of figures

• 1 eine dreidimensionale Ansicht einer Schneidmühle auf einem Stativ gemäß einer ersten Ausführungsform der Erfindung,
• 2 eine dreidimensionale Ansicht der Schneidmühle aus 1 mit geöffneter Mahlkammer,
• 3 eine dreidimensionale Ansicht der Schneidmühle aus 1 mit geöffneter Mahlkammer und entferntem Schneidrotor, entfernter Siebkassette sowie abgenommenem Mahlkammer-Verschlussdeckel,
• 4 eine dreidimensionale Ansicht des Schneidrotors und der Siebkassette für die Schneidmühle aus 1,
• 5 eine ausschnittsweise dreidimensionale Darstellung, teilweise geschnitten, des Wellendurchtritts durch die Mahlkammerrückwand der Schneidmühle aus 1,
• 6 eine Ausschnittsvergrößerung aus 5 im Bereich der Labyrinthdichtung,
• 7 eine Querschnittsdarstellung der geschlossenen Mahlkammer mit Schneidrotor der Schneidmühle aus 1,
• 8 eine Querschnittsdarstellung eines vergrößerten Ausschnitts aus 7 im Bereich der Labyrinthdichtung,
• 9 eine Ansicht des Antriebmotors für die Schneidmühle aus 1,
• 10 eine Ansicht von unten auf das Rotoraufnahmeelement der Schneidmühle aus 1,
• 11 eine Querschnittsdarstellung des Rotoraufnahmeelements aus 10 entlang der Linie 11-11,
• 12 eine Querschnittsdarstellung der Labyrinthdichtung gemäß einer weiteren Ausführungsform der Erfindung,
• 13 eine vergrößerte Darstellung des Ausschnitts A13 in 12.

Show it:

• 1 3 shows a three-dimensional view of a cutting mill on a stand according to a first embodiment of the invention,
• 2 a three-dimensional view of the granulator 1 with open grinding chamber,
• 3 a three-dimensional view of the granulator 1 with open grinding chamber and removed cutting rotor, removed sieve cassette and removed grinding chamber closure lid,
• 4 a three-dimensional view of the cutting rotor and the screen cassette for the granulator from 1 .
• 5 a partial three-dimensional representation, partially cut, the shaft passage through the grinding chamber back wall of the granulator 1 .
• 6 an excerpt from 5 in the area of the labyrinth seal,
• 7 a cross-sectional view of the closed grinding chamber with cutting rotor of the granulator 1 .
• 8th a cross-sectional view of an enlarged section of 7 in the area of the labyrinth seal,
• 9 a view of the drive motor for the granulator 1 .
• 10 a view from below of the rotor receiving element of the granulator 1 .
• 11 a cross-sectional view of the rotor receiving element 10 along the line 11-11 .
• 12 a cross-sectional view of the labyrinth seal according to another embodiment of the invention,
• 13 an enlarged view of the detail A13 in 12 ,

Detailed description of the invention

Referring to the 1-3 has the cutting mill 10 a device housing 12 on which the parts of the granulator are housed. The device housing 12 The cutting mill on a laboratory scale can eg on a tripod 8th be made ( 1 ). In the right part 12a of the device housing 12 There is a commercially available electric drive motor 14 (see. 7 . 9 ). In the present example, the in 9 illustrated drive motor 14 to a geared motor for a granulator 10 with a speed range of 50 to 700 rpm. Another embodiment of the granulator 10 works with a drive motor 14 without gear for a speed range of 300 to 3000 U / min (not shown). In the left part 12b of the device housing is the grinding chamber 16 , in which via a hopper 18 through a filling opening 19 the samples to be comminuted or the ground material can be filled during operation. The grinding chamber 16 Can be accessed from the side by opening the grinding chamber cap 20 be opened. Furthermore, the grinding chamber can be 16 by opening a Mahlkammerseitenwand, sometimes referred to as upper housing part or Mahlkammeroberteil, in this example, the Mahlkammerseitenwand 21 at which the hopper 18 attached is still open further. It should be noted that terms such as "front", "rear" or "lateral" refer to the viewpoint and are therefore not to be understood absolutely.

Referring to 7 is the drive motor 14 with a motor flange 22 to the engine side 24a the grinding chamber back wall 24 flanged. The motor shaft 26 as the primary shaft is horizontal and extends through a passage opening 28 in the grinding chamber back wall 24 through and extends into the grinding chamber 16 , On the motor shaft 26 a shaft intermediate piece is placed, which is the rotor receiving element 30 forms. The torque transmission between the motor shaft 26 and the rotor receiving element 30 is by a feather key 32 accomplished. In this example, therefore, the torque from the motor shaft 26 by means of the feather key 32 directly on the rotor receiving element 30 transfer.

The rotor receiving element 30 has a Mitnehmerflansch engine side 34 on, whose diameter is considerably larger than the diameter of the motor shaft 26 , In the driver flange 34 are eccentrically arranged driving pins 36 fastened, by means of which the torque transmission to the cutting rotor 38 is accomplished. Due to the relatively large distance between the driving pins 36 from the axis of rotation A can put a big torque on the cutting rotor 38 be transmitted. The cutting rotor 38 has corresponding receiving bores 40 for the positive engagement of the driving pins 36 in the cutting rotor 38 on. The rotor receiving element 30 and the motor shaft 26 (which may also be referred to as primary shaft) in this example together form the drive shaft 42 for the cutting rotor 38 ,

The driver flange 34 the rotor receiving element 30 or the drive shaft 42 runs at least partially within the Mahlkammerrückwand 24 or within the passage opening 28 , Therefore, in this example, the diameter d the passage opening 28 also relatively large, which in turn has a relatively large diameter of the seal of the passage opening 28 requires.

In the present embodiment, the Mahlkammerrückwand 24 formed in two parts and consists of a body part 44 made of aluminum and a grinding chamber side up or inserted plate 46 made of stainless steel. As a result, on the one hand weight can be saved and on the other hand aluminum abrasion in the grinding chamber 16 be largely avoided.

The cutting rotor 38 has a cutting rotor core 48 on which is on the drive shaft 42 is plugged and peripherally on the Schneidrotorkern 48 axially extending rotor blades 50 having. In the present example, the rotor blades 50 integrally formed. The rotor blades 50 However, they can also be used as separate cutting edges, possibly made of other material than the cutting rotor core 48 made and with the cutting rotor core 48 be connected. The cutting rotor core 48 can also be formed in two or more parts (not shown). The cutting rotor 38 can also be designed as a disk rotor, possibly with indexable inserts (not shown). The cutting rotor 38 rotates horizontally, ie around a horizontal axis A , The motor side is the cutting rotor 38 on the drive shaft 42 stored and is on the opposite side by a cone bearing 54 stored, which in turn via ball bearings 56 in the grinding chamber closure lid 20 is rotatably mounted. The cutting rotor 38 can be a taper bearing 55 include, which with a central screw 57 on the cutting rotor 38 can be attached.

Again referring to the 2-4 the cutting mill comminutes the material to be ground or the sample by cutting action between the substantially axially extending cutting edges 50 the cutting rotor 38 and the likewise substantially axially extending stationary counter-blades 52 , The granulator 10 So works on the principle of the scissors, in which the sample between a pair of blades 50 . 52 is cut. Here, "substantially axially extending" cutting edge or "axially extending" cutting edge does not necessarily mean that the cutting edges 50 . 52 exactly parallel to the axis of rotation A must run, the cutting 50 . 52 can also be axially oblique (with twist), as in the in the 2 . 4 illustrated example of a cutting rotor 38 , That in the 2 . 4 In fact, the example shown shows a cutting rotor 38 with so-called V-shaped cutting edges 50 , In the sense of a cutting mill, these cutting edges also run 50 although obliquely (with twist) but still axially or substantially axially, ie in any case not transverse or perpendicular to the axis of rotation A , The V-shaped cutting 50 the cutting rotor 38 run in principle along an acute-angled helix, which can be defined on the whole still as axial or substantially axial course. Below the cutting rotor 38 there is a screen cassette 92 through which the correspondingly finely comminuted material to be ground into the collecting container 94 can trickle out.

The grinding chamber lid 20 is apparently what causes the grinding chamber 16 with open grinding chamber lid 20 on the front for removing the cutting rotor 38 is accessible. A folding away the Mahlkammerseitenwand or Mahlkammeroberteils 21 additionally improves the accessibility of the opened grinding chamber 16 , When the grinding chamber is open 16 can the cutting rotor 38 horizontally from the drive shaft 42 subtracted from. For this purpose, the cutting rotor 38 on the drive shaft 42 only axially attached and except by the axial fixation by means of the cone bearing 54 with closed grinding chamber lid 20 not fixed axially. The cutting rotor 38 is only about the driving pins 36 positive rotationally to the drive shaft 42 coupled, but can after opening the grinding chamber cap 20 without tools from the drive shaft 42 subtracted from.

As with the rotor receiving element 30 Although a simple manual joining of the cutting rotor 38 is favored on its inclusion, is in this exemplary construction, the torque transmission means of the driving pins 36 relatively far out, which means that is sealed on a fairly large diameter (see. 3 . 5 . 7 . 8th . 10-11 ). The diameter d of the annulus on which the driving pins 36 is arranged in this example d = 55 mm, therefore, is at a driving pin diameter of 8 mm, the outer torque transmitting outer diameter D = 63 mm. In other words, the radially outer boundary of the driving pins 36 31.5 mm radially from the axis of rotation ( A ) away.

At constant speed, a large diameter, while adversely affecting the seal, will result in a relatively high peripheral speed of the seal compared to a seal hypothetically closer to the axis of rotation A would sit. In previous cutting mills, furthermore, the rotor receptacle could be removed only at great expense, and typically not for regular cleaning. The seal was previously done, for example, with felt rings that were difficult to replace. In the case of these felt rings, it could happen that they could possibly lead to adhesion, for example due to waxes, oils or resins which can be separated from the millbase.

Referring to 5-8 has the cutting mill according to the invention 10 now a labyrinth seal 60 on, which is easy for the user, for example, for cleaning, removable. In the example shown, the labyrinth seal 60 an inner labyrinth ring 62 on, which in this example as a separate part on the drive shaft 42 , more precisely on the driver flange 34 , is attached. The inner labyrinth ring 62 extends circumferentially completely around the drive shaft 42 or the driver flange 34 around and points to its engine-side back 62a a projection as the simplest type of meander shape 64a on. Furthermore, the inner labyrinth ring 62 on its Mahlkammerseite front 62b also a meander shape 64b on. The inner labyrinth ring 62 lies radially outside of the torque-transmitting driving pins 36 ,

However, it is also possible, the rotor receiving element 30 , or the driver flange 34 form directly with corresponding mill chamber side and / or motor-side labyrinth shapes or meandering, ie, the rotor receiving element 30 and the inner labyrinth ring 62 in one piece.

On the engine-side rear 24a the grinding chamber back wall 24 there is a motor-side labyrinth ring cover 66 , which with the engine-side back 62a or meander shape 64a of the inner labyrinth ring 62 is interlaced to form a corresponding labyrinth. In the present example, the motor-side labyrinth ring cover 66 integral with the grinding chamber rear wall 24 trained (cf. 7 . 8th ). The motor-side labyrinth ring cover 66 but also as one of the grinding chamber back wall 24 be formed separate part.

On the milling chamber side front 24b the grinding chamber back wall 24 , more precisely on the stainless steel attachment plate 46 , is a labyrinth-sided labyrinth ring lid 67 in a corresponding recess 68 in the grinding chamber back wall 24 or the stainless steel attachment plate 46 admitted. In the example shown, the mill chamber-side labyrinth ring cover run 67 and the grinding chamber back wall 24 or the stainless steel plate 46 flush to the area of the cutting rotor 38 together a substantially flat Mahlkammerrückwand inside 24b to build.

The rotor receiving element 30 is in the present embodiment by means of a central screw 31 on the motor shaft 26 attached, which, however, depending on the embodiment is not mandatory. The rotor receiving element 30 sits with a typical transition fit, so clamped tight on the motor shaft or primary shaft 26 , but can still overcome the clamping force of the primary shaft 26 axially in the direction of the opened grinding chamber closure lid 20 from the primary wave 26 be deducted if the possibly existing screw 31 was solved. In the in 7 . 8th shown sections, the rotor receiving element 30 a central hole 33 for the central fixing screw 31 on. To remove the rotor receiving element 30 To overcome the clamping force of the transition fit, the bore 33 be designed as a threaded hole with a larger thread diameter. Then, for example, a corresponding threaded screw in the threaded hole 33 to be used for stripping (not shown).

With the rotor receiving element 30 also becomes the inner labyrinth ring 62 and with this on the mill chamber side labyrinth ring lid 67 with deducted, so that afterwards the passage opening 28 in the grinding chamber back wall 24 ring around the primary shaft 26 relatively easily accessible, eg to clean them. In other words, the rotor receiving element decreases 30 when peeling off the primary shaft 26 the mill chamber side labyrinth ring lid 67 automatically with. Thereafter, the rotor receiving element 30 , the inner labyrinth ring 62 and / or the mill chamber-side labyrinth ring lid 67 , eg in an ultrasonic bath, are cleaned. Also the milling chamber side labyrinth ring groove 66a in the motor-side labyrinth ring cover 66 is after removal of the rotor receiving element 30 with the inner labyrinth ring 62 and the milling chamber side labyrinth ring lid 67 from the open grinding chamber 16 from easily accessible and can also be cleaned.

The thus designed labyrinth seal 60 So it is advantageously easy to maintain because it is both easy to clean and very good is durable, as the rotating parts of the labyrinth seal - the rotating with the cutting rotor inner labyrinth ring 62 and the stationary motor and mill chamber labyrinth rings 66 . 67 Do not touch, but work on the principle of the gap seal, ie an air gap between the intermeshed structures is present. Therefore, the heat development at the labyrinth seal despite the relatively large seal diameter at this point is low, since the labyrinth seal is a non-contacting gap seal and, as long as the column remain clean, here no increased friction is generated. Nevertheless, the seal on the rotor receiving element 30 or the driver flange 34 As with previous seals run far outside, whereby the compatibility with previous cutting mills can be maintained. Moreover, those immediately adjacent to the grinding chamber 16 assigning parts of the grinding chamber back wall 24 So at least the record 46 and the labyrinth ring lid taken in here 67 made of stainless steel, so that FDA compatibility is possible.

The sealing effect of the labyrinth seal 60 can now be further improved by further measures.

Referring to the 5 . 6 is a first possible measure to further improve the sealing effect of the labyrinth seal 60 in the generation of an air flow from the motor side in the direction of the grinding chamber 16 , For example, on the circumferential outside 62c of the inner labyrinth ring 62 fan blades 72 be provided. These fan blades 72 For example, they can be milled out relatively easily. The air flow or a dynamic pressure is thus through the rotor receiving element 30 or the inner labyrinth ring placed thereon 62 generated. In this regard, because of the large peripheral speeds with respect to the gasket, the large diameter problematic in terms of airflow generation in the labyrinth seal may be 60 be used synergistically positive.

During rotation of the inner labyrinth ring 62 generate the fan blades 72 So an air flow and therefore form an air flow generating device 73 , It would also be conceivable, for example, an external pump as air flow generating device 73 ,

Referring to 7 the air supply is through an air duct 74 in the engine side 24a the grinding chamber back wall 24 guaranteed. The air flow is indicated by the arrow 76 visualized. As a result, the relatively large motor flange can still be used 22 a commercially available drive motor 14 to the grinding chamber back wall 24 be flanged.

The airflow 76 passes through the ventilation duct 74 and through the labyrinth seal 60 from the the drive motor 14 surrounding space outside the grinding chamber 16 into the grinding chamber 16 on. By this means of the air flow generating device 73 forced airflow 76 can the "sealing effect" of the labyrinth or gap seal 60 be further improved.

Referring to 12 . 13 Below is yet another way to improve the labyrinth seal 60 proposed, wherein the basic structure is the same as in the 1-11 so that reference may be made to the description herein to avoid repetition.

The difference to the embodiment in the 1-11 with the air flow generating device 73 is due to the fact that the embodiment of the 12 . 13 additional labyrinth elements 82 (instead of fan blades 72 for generating a forced airflow 76 ) contains. The inner labyrinth ring used here 62 has at its radially outer periphery 62c meandering formations 82 on. The meandering formations 82 are in the present example by two in the axial cross section triangular rings 84 . 86 educated. As in the sectional view of 12 is recognizable, is the cylindrical outer surface 62c of the inner labyrinth ring 62 provided with sharp-edged tips. Through the rotation of the inner labyrinth ring 62 For example, this geometry can form vortices that can cause air pockets and thus the passage of particles from the grinding chamber 16 in the direction of the engine 14 surrounding area can complicate or prevent. An advantage of this inner labyrinth ring 62 is that it can be produced as a pure turned part and does not need to be milled. In the present example, the inner labyrinth ring 62 at its radially outer peripheral side 62c Meander-shaped projections, for example in the form of two radially outwardly tapered axially offset rings 84 . 86 , on. The in relation to the inner labyrinth ring 62 surrounding inner ring wall 28d the passage opening 28 does not point into the spaces between the protrusions 84 . 86 engaging counter labyrinth rings, so that one can speak of an open labyrinth on the peripheral side or translucent labyrinth. In other words, the radially outwardly extending annular projections 84 . 86 not interlocked with corresponding counter labyrinth elements. Advantageously, the inner labyrinth ring remains 62 axially out of the passage opening 28 pulled out.

Referring to the 7 . 8th . 12 is the mill chamber-side labyrinth ring lid 67 positive fit with an O-ring 88 clamped in the recess 68 in the plate 46 used. The elastic O-ring 88 on the one hand ensures a good clamping retention of the labyrinth ring cover 67 in the grinding chamber back wall 24 , but also leaves the axial withdrawal of the rotor receiving element 30 together with the inner labyrinth ring 62 and the mill chamber side labyrinth ring lid 67 while overcoming the through the O-ring 88 caused clamping force too. The user can therefore with appropriate axial force to overcome the clamping force of the clamping parts 30 . 62 and 67 from the passage opening 28 pull out so that the passage opening 28 and the motor-side labyrinth ring cover 66 front side at least partially accessible for cleaning. In other words, the labyrinth seal 60 relatively easy to be pulled apart axially, especially by hand, to be accessible for cleaning.

In summary, the sealing concept presented here fulfills a number of advantages, e.g. compared to previously used felt seals.

The sealing concept is easy to maintain and requires hardly any maintenance. Nevertheless, the sealing concept keeps dust well in the milling chamber and leaves little dust through the labyrinth seal in the area of the drive motor 14 reach. Furthermore, the sealing concept has a low heat development. Nevertheless, the labyrinth seal can 60 on an existing rotor receiving element 30 run relatively far out, which can get the compatibility with cutting mills of the earlier types.

A special advantage is the avoidance of a material abrasion (with a clean labyrinth) and the possibility of an FDA approval, especially if eg the parts 62 . 66 . 67 the labyrinth seal 60 and the plate 46 are made of stainless steel. The production of such a labyrinth seal 60 has proven to be technologically feasible despite the relatively large diameter and is in some cases even having surprising advantages. At present, for example, efforts are increasing in many regions of the world to allow cannabis products for various applications. This has led to increased demand for granulators in cannabis processing. In particular, in the comminution of the oil-containing cannabis flowers, but in part also the cannabis leaves, it has been shown that the proposed here labyrinth seal in a granulator can effectively prevent oiling or hardening of the seal, or at least significantly improves the cleaning options.

It will be apparent to those skilled in the art that the above-described embodiments are to be read by way of example, and that the invention is not limited to them, but that they can be varied in many ways without departing from the scope of the claims. It is also to be understood that the features, independently as they are disclosed in the specification, claims, figures, or otherwise, also individually define essential components of the invention, even if described together with other features.

Claims (21)

A cutting mill (10) for cutting samples, comprising: a device housing (12), a drive motor (14) and a drive shaft (42), a grinding chamber (16) with a cutting rotor (38) arranged therein for cutting the samples in the grinding chamber (16), wherein the cutting rotor (38) defines an axis of rotation (A) and the grinding chamber (16) axially on the motor side of a Mahlkammerrückwand (24 ), wherein the grinding chamber rear wall (24) has a shaft passage opening (28) through which the cutting rotor (38) can be driven by the drive shaft (42), wherein the shaft passage opening (28) in the grinding chamber rear wall (24) is sealed by a labyrinth seal (60). Cutting mill (10) after Claim 1 in that the device housing (12) comprises an axially end-side closure lid (20) which can be opened to open the grinding chamber (16) and in which the cutting rotor (38) is rotatably mounted (54) on the axial side opposite the drive motor (14) , 56) when the closure lid (20) is closed. A cutting mill (10) according to any one of the preceding claims, wherein the cutting rotor (38) is coaxially attachable and detachable to the drive shaft (42) when the grinding chamber (16) is opened. A cutting mill (10) as claimed in any one of the preceding claims, including follower elements (36) which positively engage the cutting rotor (38) when the cutting rotor (38) is mounted on the drive shaft (42) to apply the torque by means of the driver elements (38). 36) to the cutting rotor (38). The granulator (10) according to any one of the preceding claims, wherein the drive shaft (42) is multi-piece and comprises at least a primary shaft (26) and a rotor receiving member (30) coaxially mounted on the primary shaft (26), and wherein coupling means (32) are interposed between the rotor Primary shaft (26) and the rotor receiving element (30) are included, which transmits the torque from the Primary shaft (26) on the rotor receiving element (30) effect. A granulator (10) as claimed in any one of the preceding claims, wherein the drive shaft (42) includes a cam flange (34) extending around the drive shaft (42) and wherein the cam members (36) are in the driver flange (34) on the one hand and in the cutting rotor (38) engage. The cutting mill (10) according to any one of the preceding claims, wherein the driver elements (36) are formed as axially extending driver pins whose radially outer boundary is at least 15 mm radially away from the axis of rotation (A). Cutting mill (10) after Claim 6 or 7 wherein the Mitnehmerflansch (34) is formed as a part of the rotor receiving element (30) and the rotor receiving member (30) with the Mitnehmerflansch (34) as a unit on the primary shaft (26) can be plugged. Cutting mill (10) according to one of Claims 6 - 8th wherein the Mitnehmerflansch (34) is at least partially disposed within the shaft passage opening (28). Cutting mill (10) according to one of the preceding claims, wherein the labyrinth seal (60) comprises an inner labyrinth ring (62) and a mill chamber-side labyrinth ring cover (67), and a mill chamber-side axial end face (62b) of the inner labyrinth ring (62) is intermeshed with an axial end face of the mill chamber labyrinth ring cap (67) and / or wherein the labyrinth seal (60) comprises an inner labyrinth ring (62) and a motor-side labyrinth ring cover (66), and wherein an engine-side axial end surface (62a) of the inner labyrinth ring (62) is interlocked with an axial end face of the motor-side labyrinth ring cover (66). Cutting mill (10) after Claim 10 wherein the grinding chamber rear wall (24) has a grinding chamber-side annular recess (68) in which the mill chamber-side labyrinth ring cover (67) is fixed. Cutting mill (10) after Claim 10 or 11 in which the inner labyrinth ring (62) can be pulled off in the direction of the motor (14) to the grinding chamber (16) and the mill chamber-side labyrinth ring cover (67) is clamped in the grinding chamber rear wall (24) and the labyrinthine labyrinth ring cover (62) is removed when the inner labyrinth ring (62) is withdrawn 67) is released from the clamping in the grinding chamber rear wall (24) and can be pulled off the drive shaft (42) with the inner labyrinth ring (62). Cutting mill (10) according to one of Claims 10 - 12 , wherein the mill chamber-side labyrinth ring cover (68) is clamped in the mill chamber-side annular recess (68) by means of a form-fitting inserted O-ring (88). Cutting mill (10) according to one of Claims 10 - 13 , wherein the inner labyrinth ring (62) is arranged radially outward on the rotor receiving element (30), in particular radially outward on the driver flange (34). A granulator (10) as claimed in any one of the preceding claims, including air flow generating means (73) which generates an airflow (76) through the gap of the labyrinth seal (60). Cutting mill (10) according to one of Claims 10 - 15 wherein the inner labyrinth ring (62) has fan blades (72) which generate airflow through the gap of the labyrinth seal (60) upon rotation of the inner labyrinth ring (62). Cutting mill (10) after Claim 16 wherein the fan blades (72) are disposed on a radially outer circumferential wall (62c) of the inner labyrinth ring (62). A cutting mill (10) according to any one of the preceding claims, wherein between the grinding chamber rear wall (24) and the drive motor (14) is provided a ventilation duct (74) through which an air flow (76) is passed through the labyrinth seal (60). The granulator (10) of any one of the preceding claims, wherein the labyrinth seal (60) comprises an inner labyrinth ring (62), the shaft passage opening (28) having an inner radial annular wall (28d) within which the inner labyrinth ring (62) is disposed in that the inner radial annular wall (28d) surrounds the inner labyrinth ring (62) in an annular manner, wherein either the inner radial annular wall (28d) or the outer radial annular wall (62c) of the inner labyrinth ring (62) has a meandering cross section (82, 84, 86), but the inner radial annular wall (28d) and the outer radial annular wall (62c) of the inner labyrinth ring (62) are not intermeshed such that the inner labyrinth ring (62) is nevertheless axially withdrawable from the shaft penetrating opening (28). Cutting mill (10) after Claim 19 , wherein the meandering shape (82, 84, 86) in the axial cross section is formed radially tapering. Cutting mill (10) after Claim 20 , Wherein the meandering shape in the axial cross-section triangular, possibly triangular pointed (84, 86).

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