EP3383542B1 - Millstone arrangement for a flat burr grinder for grinding material to be ground - Google Patents

Description

The invention relates to a grinding stone arrangement for a disc grinder for the comminution of grist, in particular granular material in the food sector, consisting of a fixed, stator grinding disc and a driven, rotor grinding disc, which are arranged concentrically one above the other while maintaining a grinding gap, the stator grinding disc having a central opening for giving up the Has grist and the grinding disks consist of a natural or artificial stone material, according to claim 1.

Grinding stone arrangements for grain mills have been state of the art for many decades. Basically, such a grinding stone arrangement, which forms the actual grinder, consists of two ring-shaped grinding stones. A first millstone is usually designed to be stationary. A second grinding stone is connected to a drive and is able to execute a rotational movement. On the stationary grinding stone, also known as a stator grinding stone, there is an inlet opening or an inlet funnel for the ground material, e.g. grains.

The rotating grinding stone is usually located on a rotor hub which is located on a shaft driven by an electric motor. A millstone assembly according to the preamble of claim 1 is in US Pat U.S. 3,926,380 A disclosed.

From the DE 84 35 448 U1 a grinding stone made of natural and artificial stone material is previously known, at least one of the grinding surfaces having a recess protruding radially from a central opening. In side view, this recess has wedge contours with an inclined bottom surface that rises only in the direction of rotation and two at least approximately axially aligned boundary surfaces, with a planar hub area extending in the direction of rotation from the edge of the recess to the next edge of the recess. With such a formation of wedge contours, the grinding performance should increased and the temperature of the grist can be reduced during the grinding treatment.

With the granulate mill for plastic waste according to DE 195 30 428C1 it is assumed that a grinding disc which preferably revolves in a horizontal plane and can be driven about a vertical axis, to which cutting bodies are attached. The cutting bodies protrude from the top of the grinding disc. Above the grinding disk, at least one radially extending, stationary cutting bar is arranged, which has edge recesses corresponding to the contour of the cutting bodies in the direction of rotation, through which the cutting bodies move when the grinding disk is rotated. The cutting bodies are mounted on cutting body holders that can be inserted in receptacles. With this further development of a granulate mill with preferably acute-angled cutting edges, when plastic waste is fed in, there is a cutting process and thus a pre-comminution of the ground material.

From the DE 10 2010 043 353 A1 a processing body for comminuting a feed material is previously known. This is about the grinding of granular materials, which require wear-resistant processing bodies.

In this sense, the processing body for comminuting a feed material comprises a cast metal body as a cast metal body and at least one insert body which is embedded in the cast carrier matrix and increases the wear resistance of a functional or wear surface of the processing body.

The at least one insert body is a pressed or sintered body of a mixture of metal powder and hard material or a die-cast body which comprises a hard material in a die-cast matrix made of die-cast metal.

In the case of the grinding tool for comminuting granular material from the food sector according to EP 1 818 099 A1 is based on an internal grinding body in the form of a grinding cone, the grinding cone being surrounded by a fixed grinding ring, forming a grinding gap. To simplify the assembly of such a grinding tool, the grinding cone is located rotatably in a bearing via a coaxial, at least cylindrical in the bearing area Drive shaft indirectly connected to the drive. The drive shaft and the grinding cone are formed in one piece.

From the above, it is the object of the invention to provide a further developed grinding stone arrangement and a disc grinder for comminuting ground material, in particular granular material in the food sector, which is able to achieve the same grinding performance with less energy input with regard to the drive of the grinding mechanism, an undesirable increase the temperature of the grist is prevented from being crushed.

The object of the invention is achieved by means of a grinding stone arrangement according to the combination of features according to patent claim 1, the subclaims representing at least useful embodiments and developments.

It is therefore based on a grinding stone arrangement for a disc grinder for comminuting grist. This grist is in particular a granular material in the food and food sector. The grinding stone arrangement consists of a fixed stator grinding disk and a driven rotor grinding disk.

The stator grinding disk and rotor grinding disk are arranged concentrically one above the other while maintaining a grinding gap, which is optionally adjustable.

The stator grinding disk has a central or central opening for feeding in the grist. The grinding discs are made of a natural or artificial stone material.

According to the invention, the stator grinding disk has a first insert, connected to the grinding disk and directed both towards the center of the opening and towards the grinding gap, in the area surrounding the opening for feeding the material to be ground.

Furthermore, the rotor grinding disk has a second insert connected to it in a rotationally fixed manner, which in longitudinal section has the shape of a cone or a Has truncated cone, wherein the cone or truncated cone tip protrudes into the opening for the grinding stock feed.

The first and the second insert have a structure on their surfaces directed towards the grinding gap and / or towards the opening.

According to the invention, the material of the inserts is also chosen differently from the material of the grinding disks.

The inserts are preferably made of a ceramic material, metal or plastic of greater hardness.

The aforementioned structuring is designed as a toothing and has a large number of cutting or impact edges.

The toothing of the insert of the rotor grinding disk is preferably designed to run in an arc shape radially to the center outwards.

The toothing of the insert of the stator grinding disk is designed both in the direction of the axis of rotation of the rotor grinding disk and in the direction of the grinding gap.

Between the insert of the stator grinding disc and the insert of the rotor grinding disc, a conical annular gap for the grinding stock feed is provided in the area of the opening for feeding in the grist.

The curved toothing can have at least one point of discontinuity per curved groove or have a spiral course.

The grinding disk inserts are flush with the surface of the respective grinding disk in the area of the grinding gap, which is essentially usually horizontal. The pre-comminuted ground material is therefore introduced into the remaining grinding gap between the stator and rotor grinding disks for fine grinding.

By means of the grinding disk inserts, a pre-grinding of the ground material is possible, its fine grinding via the grinding gap between the remaining unused sections of the stator and rotor grinding disk is realized.

The invention is to be explained in more detail below using an exemplary embodiment and with the aid of figures.

Fig. 1

eine Draufsicht auf eine Mahlsteinanordnung mit Blick in Richtung Öffnung zur Aufgabe des Mahlguts mit erkennbarer Rotormahlscheibe, welche eine Strukturierung in Form einer Verzahnung aufweist, sowie mit erkennbaren Verzahnungsabschnitten der Statormahlscheibe bzw. des Einsatzes der Statormahlscheibe;

Fig. 2

eine perspektivische Draufsicht auf die Rotormahlscheibe, welche einen Einsatz in Kegelstumpfform besitzt, wobei die Oberfläche des Einsatzes eine Verzahnung aufweist, die bogenförmig vom Zentrum des Einsatzes zum äußeren Rand eine Vielzahl von Nuten aufweist und wobei die Nuten eine Unstetigkeitsstelle in ihrem bogenförmigen Verlauf besitzen;

Fig. 3

eine Draufsicht auf die zum Mahlspalt gerichtete Unterseite der Statormahlscheibe mit Einsatz, wobei der Einsatz eine Verzahnungsstruktur sowohl radial als auch axial verlaufend besitzt, und

Fig. 4

eine Längsschnittdarstellung durch eine Mahlsteinanordnung, umfassend Statormahlscheibe und Rotormahlscheibe, welche die erfindungsgemäßen Einsätze aufweist.

Here show:

Fig. 1

a plan view of a grinding stone arrangement with a view in the direction of the opening for feeding the ground material with a recognizable rotor grinding disk, which has a structure in the form of a toothing, as well as with recognizable toothing sections of the stator grinding disk or the insert of the stator grinding disk;

Fig. 2

a perspective top view of the rotor grinding disk, which has an insert in the shape of a truncated cone, the surface of the insert having a toothing which has a plurality of grooves in an arc from the center of the insert to the outer edge and the grooves have a point of discontinuity in their arcuate course;

Fig. 3

a plan view of the underside of the stator grinding disk with insert facing the grinding gap, the insert having a toothed structure extending both radially and axially, and

Fig. 4

a longitudinal sectional view through a grinding stone arrangement, comprising stator grinding disk and rotor grinding disk, which has the inserts according to the invention.

The longitudinal section after Fig. 4 shows the basic design of a grinding stone arrangement for a disc grinder, comprising a stator grinding disk 10 and a rotor grinding disk 20.

The rotor grinding disk 20 is non-rotatably connected to a drive device (not shown).

The millstone arrangement according to the schematic diagram according to Fig. 4 also has a central opening 3 for feeding the grist, not shown.

Between the stator grinding disk 10 and the rotor grinding disk 20 there is a grinding gap 4, which is provided by a spaced-apart mounting of the grinding disks 10; 20 is obtained.

In the area surrounding the opening 3, the stator grinding disk 10 has a first insert 1 which is connected to the grinding disk and directed both towards the center of the opening 3 and towards the grinding gap 4.

Furthermore, the rotor grinding disk 20 has a second insert 2 which is connected to it in a rotationally fixed manner and has the shape of a cone or a truncated cone in longitudinal section.

The cone or truncated cone tip 5 extends into the opening 3 for the grinding stock feed.

As from the Figs. 1 to 3 can be removed, both the first insert 1 and the second insert 2 have a structuring, for example designed as a toothing, on their surface facing the grinding gap and / or the opening.

The material of the stator grinding disk 10 and the rotor grinding disk 20 is natural or artificial stone. The material of the inserts 1; 2 is preferably ceramic, metal or a plastic of greater hardness.

From the Figs. 1 to 3 it can be seen that the structure designed as a toothing has a large number of cutting or impact edges.

The toothing of the insert 2 of the rotor grinding disk 20 runs, as in FIG Fig. 2 seen, arcuate radially outward from the center of the insert.

There may be points of discontinuity in the arcuate course.

The recognizable grooves of the toothing take up the grinding stock, which is moved outward by the rotational movement of the rotor in conjunction with the centrifugal forces that occur and passes into the remaining grinding gap between the stator grinding disk 10 and rotor grinding disk 20 for fine grinding.

The Fig. 3 makes it clear that between the insert 1 of the stator grinding disk 10 and the insert 2 of the rotor grinding disk 20 in the area of the opening 3 for feeding in the ground material, a conical annular gap 6 can be formed for the ground material.

From the Fig. 4 it can also be seen that the grinding disc inserts 1; 2 in the area of the grinding gap 4 with the surface of the respective grinding disk 10; 20 flush.

With the task of the grist via the opening 3, the action of the inserts 1; 2 and their surface structuring for a pre-comminution of the ground material, the fine comminution of which is realized via the grinding gap 4 between the remaining, unused sections of the stator and rotor grinding disks.

Claims (7)

1. A millstone arrangement for a flat burr grinder for grinding material to be ground, in particular granular material in the food sector, composed of a fixed stator grinding disc (10) as well as a driven rotor grinding disc (10), which are superimposed concentrically while keeping a grinding gap (4), wherein the stator grinding disc (10) has a centric opening (3) for feeding the material to be ground, and the grinding discs (10; 20) are composed of a natural stone material or an artificial stone material, the rotor grinding disc (20) furthermore has a second insert (2) being in connection with it in a torque-proof manner, which insert has the shape of a cone or a truncated cone in a longitudinal section, wherein the tip (5) of the cone or the truncated cone protrudes into the opening (3) for feeding the material to be ground, and the second insert (2) has a structuring at its surfaces directed toward the grinding gap (4) and/or toward the opening (3),
   characterized in that
   in the area surrounding the opening (3) for feeding the material to be ground, the stator grinding disc (10) has a first insert (1) having a structuring, which insert is in connection with the grinding disc (10) and directed both toward the center of the opening (3) and toward the grinding gap, the structuring is formed as a toothing extending radially and axially, i.e. both in the direction of the axis of rotation of the rotor grinding disc (20) and toward the grinding gap (4), and the material of the inserts (1; 2) is selected to be different from the material of the grinding discs (10; 20).
2. The millstone arrangement according to claim 1,
   characterized in that
   the inserts (1; 2) consist of ceramics or metal.
3. The millstone arrangement according to any one of the preceding claims,
   characterized in that
   the toothing has a plurality of cutting edges or impact edges.
4. The millstone arrangement according to claim 3,
   characterized in that
   the toothing of the insert (2) of the rotor grinding disc (20) is formed to extend in an arcuate manner radially outward from the center.
5. The millstone arrangement according to any one of the preceding claims,
   characterized in that
   between the insert (1) of the stator grinding disc (10) and the insert (2) of the rotor grinding disc (10), a conical annular gap (6) for the material to be ground is formed in the area of the opening (3) for feeding the material to be ground.
6. The millstone arrangement according to claim 4,
   characterized in that
   the toothing extending in an arcuate manner has at least one point of discontinuity per arcuate groove.
7. The millstone arrangement according to any one of the preceding claims,
   characterized in that
   the grinding disc inserts (1; 2) are flush with the upper surface of the respective grinding disc (10; 20) in the area of the grinding gap (4).

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