GRAIN MILL

Description

[0001] The invention relates to a grain mill according to claim 1.

[0002] Grain mills are known having a housing with a longitudinal axis, the housing having a base part and a cover part, an inlet opening arranged in the cover part, a motor arranged in the base part, and an annular millstone arranged in the housing, in which a rotor driven by the motor is arranged concentrically. The motor generates an air stream by means of which the grain introduced into the housing is accelerated in rotation against the millstone. During this movement, the grain is ground into flour by the millstone. Such grain mills are also known under the term Zentrofan mills. Examples of Zentrofan mills are disclosed in DE 10 2004 022 870 A1 and NZ 237 879 A; another type is disclosed in WO 2004 / 112963 A2.

[0003] It is common to use a natural millstone, such as one made of lava rock, as a millstone. However, the pores in the natural millstone become clogged over time, impairing the grinding result. Furthermore, such a millstone is not easy to clean. Consistent quality cannot be guaranteed, as the natural stone has varying degrees of pores.

[0004] The object of the invention is therefore to further develop a grain mill in such a way that it is easier to clean and, in particular, the grinding result can be improved or a consistent quality can be achieved.

[0005] The object is achieved according to the invention by a grain mill having the features of patent claim 1.

[0006] Advantageous embodiments and further developments are specified in the dependent claims.

[0007] The grain mill according to the invention, comprising a housing with a longitudinal axis, a wall, a base part, and a lid part, wherein an inlet opening is arranged in the lid part, wherein a motor which drives a rotor is arranged on the base part, and wherein the grain mill has an annular millstone, is characterized in that the millstone has a diamond or sapphire coating, at least in sections. Such a coating is self-cleaning due to its surface. Due to a defined coating area, a continuously consistent result can be achieved. Furthermore, a diamond or sapphire coating can achieve a particularly fine grinding result, since the roughness of the coating can be specifically influenced.Another fundamental advantage over a natural grinding stone is the strength of the diamond or sapphire layer, which does not wear out and therefore does not contaminate the ground material.

[0008] Preferably, the millstone has an inner and an outer side, with the diamond or sapphire layer arranged on the inner side. Typically, only the inner side of the millstone comes into contact with the grain to be ground.

[0009] Preferably, the diamond or sapphire layer has a thickness of less than 3 mm, preferably less than 1 mm. A layer as thin as possible can enable more cost-effective production.

[0010] Particularly preferably, the diamond or sapphire layer has a roughness between 10 µm and 100 µm, whereby a particularly fine grinding result can be achieved.

[0011] According to a particularly preferred embodiment of the invention, the millstone is made of metal, ceramic, or plastic. This simplifies production compared to using a natural millstone.

[0012] Preferably, the rotor is arranged concentrically within the millstone. This allows for a space-saving arrangement. Furthermore, it enables particularly favorable rotational acceleration of the grain to be ground.

[0013] A particularly advantageous development of the invention provides for the rotor to be designed as an impeller with a rotor disk. Such a rotor can generate air turbulence inside the housing, which is particularly favorable for a fine grinding result.

[0014] Preferably, the rotor disk has a plurality of radially extending first vanes on its side facing away from the motor. Such first vanes can facilitate the transport of the ground grain into the upper area of the housing, from where it can usually be discharged.

[0015] Advantageously, the rotor disc has several second vanes on its side facing the motor, which are curved toward the radius or at least partially angled. Such second vanes can promote the rotational acceleration of the grain fed into the housing against the millstone.

[0016] Preferably, the number of first vanes is greater than the number of second vanes, in particular twice as large, which can further improve the flow conditions inside the housing.

[0017] According to a preferred embodiment, the millstone is arranged fixedly in the housing, which enables a simple structural design of the grain mill.

[0018] Preferably, the motor's rotational axis coincides with the longitudinal axis of the housing. This allows for a rotationally symmetrical flow distribution within the housing, which can achieve a uniform grinding result.

[0019] Preferably, a funnel is located at the inlet opening. This simplifies the filling of the grain into the grain mill.

[0020] According to a particularly preferred embodiment of the invention, a downpipe is arranged in the housing, which extends in particular to an adapter, which is arranged in particular between the motor and the rotor. This enables a targeted supply of grain between the millstone and the rotor.

[0021] Advantageously, a radial discharge opening is arranged on the housing, particularly between the rotor and the cover part, particularly in an upper mill housing. The ground grain is guided by the air flow into the upper area near the cover of the housing, where it can be discharged radially.

[0022] An embodiment of the invention is explained in detail with reference to the following figures. Fig. 1 a side view of an embodiment of a grain mill according to the invention, Fig. 2 a further side view of the grain mill according to Fig. 1 , Fig. 3 a plan view of the grain mill according to Fig. 1 , Fig. 4 a view from below of the grain mill according to Fig. 1 , Fig. 5a longitudinal section through the grain mill along the line BB in Fig. 4 , Fig. 6 a perspective view of the millstone of the grain mill according to Fig. 5 , Fig. 7 a longitudinal section through the millstone according to Fig. 6 , Fig. 8 an enlarged detail from Fig. 7 , Fig. 9 a perspective view of the rotor of the grain mill according to Fig. 5 , Fig. 10a further perspective view of the rotor according to Fig. 9 , Fig. 11 a side view of a first blade of the rotor according to Fig. 9 , Fig. 12 a side view of a second blade of the rotor according to Fig. 9 and Fig. 13 a plan view of the second wing according to Fig. 12 .

[0023] The Figures 1 to 5 show various views of a first embodiment of a grain mill 10 according to the invention, wherein for the sake of clarity not all reference numbers are indicated in all figures.

[0024] The grain mill 10 has a housing 20 with a longitudinal axis 1G. The housing 20 has a wall 21, a base part 22, and a cover part 23, wherein the base part 21 or the cover part 22 can also be formed integrally with the wall 21. In particular, the wall 21 is cylindrical, preferably circular-cylindrical. An inlet opening 24 is arranged in the cover part 23, which is arranged, in particular, concentrically around the longitudinal axis 1G. A hopper 25 can be arranged at the inlet opening 24.

[0025] A motor 30 is arranged on the base part 22, in particular such that a housing 32 of the motor 30 is arranged on the outside of the base part 22. The motor 30 drives a rotor 40, which is arranged in particular in the housing 30. The motor 30 has a rotational axis lM, which in particular coincides with the longitudinal axis lG of the housing.

[0026] The grain mill 10 has an annular millstone 50 (see in particular Figure 5 ), which is arranged in particular in a fixed manner in or on the housing 20. The Figures 6 to 8show various views of the millstone 50, wherein, for clarity, not all reference numerals are indicated in all figures. The millstone 50 has, at least in sections, a diamond or sapphire layer 52. The millstone 50 has an inner side 51a and an outer side 51b, wherein the diamond or sapphire layer 52 is arranged in particular on the inner side 51a. Preferably, the entire inner side 51a is covered with the diamond or sapphire layer 52. The diamond or sapphire layer 52 can have a thickness d of less than 3 mm, preferably less than 1 mm, particularly preferably between 0.1 mm and 0.5 mm. The diamond or sapphire can, for example, be embedded in a carrier layer made of nickel, thereby establishing the connection to the millstone 50. Furthermore, the diamond or sapphire layer 52 can have a roughness between 10 µm and 100 µm.

[0027] The millstone 50 itself can be made of metal, ceramic, or plastic. As in Figure 5 As can be seen, the grinding stone 50 is arranged as an independent component in the housing 20. However, it is also possible for the wall 23 of the housing to form the grinding stone 50 and for the diamond or sapphire layer 52 to be applied directly to the inside of the wall 23.

[0028] The rotor 40 is preferably arranged concentrically in the millstone 50. The arrangement of the rotor 40 in the millstone 50 is intended, in particular, to mean that the sections along the longitudinal axis 1G, in which the rotor 40 and the millstone 50 are arranged, overlap, and preferably the shorter of the two sections is arranged entirely within the longer of the two sections.

[0029] The Figures 9 to 13show various views of the rotor 40 as well as parts of the rotor 40, whereby for the sake of clarity not all reference numbers are indicated in all figures.

[0030] The rotor 40 can be designed as an impeller with a rotor disk 41. The plane of the rotor disk 41 is arranged, in particular, perpendicular to the rotational axis lM of the motor or the longitudinal axis lG of the housing 20. The rotor disk 41 has a side 41a facing away from the motor 30 and a side 41b facing the motor 30. The rotor disk 41 can have a plurality of radially extending first vanes 44 on its side 41a facing away from the motor 30 (cf. Figures 9 and 11 ). The first wings 44 can be plate-like with a pentagonal outline, which in particular includes three right angles (cf. Figure 11). The first vanes 44 can be inserted into recesses 48 of the rotor disk 41 via projections 44a arranged on a side edge and secured thereover. The rotor disk 41 can have, on its side 41b facing the motor 30, a plurality of second vanes 46 that are bent toward the radius or at least partially angled (cf. Figures 10, 12 and 13 ). The second wings 44 can be plate-like with a rectangular outline, wherein they are each bent along two parallel bending edges 47 at an angle α1, α2 (cf. Figures 12 and 13 ). The angles α1, α2 between the bent outer partial surfaces and the central surface, which is arranged between the two bent edges 47, can be, for example, approximately 165° (cf. Figure 13Instead of bending the second vanes 46, they can also be curved accordingly. The second vanes 46 can be inserted into recesses 48 of the rotor disk 41 via projections 46a arranged on a side edge and secured thereon.

[0031] The number of first vanes 44 is preferably greater than the number of second vanes 46, in particular twice as large. In the present embodiment, nine second vanes 46 and eighteen first vanes 44 are arranged on the rotor disk 41.

[0032] The grain mill 10 can have a downpipe 27 with a first end 27a and a second end 27b. The grain to be milled can be fed via the downpipe 27. The first end 27a of the downpipe 27 can, for example, connect to the inlet opening 24 in the cover part 22 and / or to the hopper 25. The second end 27b of the downpipe 27 is arranged in particular in the region of an adapter 71, which is arranged in particular between the motor 30 and the rotor 40.

[0033] An outlet opening 29 can be arranged on the housing 20, in particular an upper mill housing 29, which can be arranged in particular between the rotor 40 and the cover part 22. Through this outlet opening, the ground grain can be discharged into a collecting container, wherein a filter element can be arranged in particular between the outlet opening 29a and the collecting container. If the ground grain is moved in a rotational manner in the housing 20, it can in particular be discharged tangentially. For this purpose, a further rotor 60 can be arranged in particular in the upper mill housing 29, which rotor preferably only has in particular radially extending blades 62.

[0034] A replaceable insert disc 28 can be inserted between the housing 20 and the upper mill housing 29. This insert disc has a defined inner diameter that can determine the degree of grinding. The grinding degree can be determined by changing the diameter of the insert disc 28. The grinding material is rubbed against the millstone 50 by centrifugal force until it evaporates and moves toward the center of the downpipe 27, where it enters the upper mill housing 29.

[0035] A grinding process with the grain mill 10 can be carried out, for example, in the following manner. The motor 30 is switched on and the rotor 40 is set in motion. The grain to be ground is then poured through the hopper 25 into the housing 20 and falls through the downpipe 27 into the area of the rotor 40. The rotor 40 generates an air flow through the air supply opening 70, which accelerates the grain rotationally and moves it against the inner side 51a of the millstone 50. The grain kernels rub against the diamond or sapphire layer 52 of the millstone 50 and are ground into fine flour dust. The flour dust is moved by the air flow and migrates into the upper mill housing 29. The insert disc 28, in particular, determines how long the material to be ground is ground. The fine flour dust collects in the upper mill housing 29 and can be discharged radially through the discharge opening 29a.The discharged flour dust can be collected in a collecting container (not shown), in particular after passing through a filter with which any coarser grain particles that may still be present can be filtered out. List of reference symbols

[0036] 10Grain mill 20Housing 21Wall 22Base 23Cover 24Inlet opening 25Funnel 27Downpipe 27aFirst end 27bSecond end 28Insert disc 29Upper mill housing 29aOutlet opening 30Motor 40Rotor 41Rotor disc 41aSide 41bSide 44First wing 44aProtrusion 46Second wing 46aProtrusion 47Knee-end 48Recess 50Grindstone 51aInside 51bOutside 52Diamond or sapphire coating 60Additional rotor 62Wing 70Air supply opening 71Adapter lGLongitudinal axis lmAxis of rotation dThickness α1Angle α2Angle

Claims

1. Flour mill (10) comprising a housing (20) having a longitudinal axis (lG), which has a wall (21), a base part (22) and a cover part (23), wherein an insertion opening (24) is arranged in the cover part (23), wherein a motor (30) is arranged on the base part (22), which motor drives a rotor (40), and wherein the flour mill (10) comprises an annular grindstone (50), wherein the grindstone (50) comprises a diamond or sapphire layer (52) at least in portions.

2. Flour mill according to claim 1, characterised in that the grindstone (50) has an inside (51a) and an outside (51b), wherein the diamond or sapphire layer (52) is arranged on the inside (51a).

3. Flour mill according to either of the preceding claims, characterised in that the diamond or sapphire layer (52) has a thickness (d) of less than 3 mm, preferably less than 1 mm.

4. Flour mill according to any of the preceding claims, characterised in that the diamond or sapphire layer (52) has a roughness between 10 µm and 100 µm.

5. Flour mill according to any of the preceding claims, characterised in that the grindstone (50) is produced from metal, ceramic or plastics material.

6. Flour mill according to any of the preceding claims, characterised in that the rotor (40) is arranged concentrically in the grindstone (50).

7. Flour mill according to any of the preceding claims, characterised in that the rotor (40) is configured as an impeller wheel having a rotor plate (41).

8. Flour mill according to claim 7, characterised in that the rotor plate (41) comprises a plurality of radially extending first blades (44) on its side (41a) facing away from the motor (30).

9. Flour mill according to either of claims 7 to 8, characterised in that the rotor plate (41) comprises a plurality of second wings (46), curved against the radius or extending at an angle at least in portions, on the side thereof facing the motor (30).

10. Flour mill according to claims 8 and 9, characterised in that the number of first wings (44) is greater than the number of second wings (46), in particular double.

11. Flour mill according to any of the preceding claims, characterised in that the grindstone (50) is arranged in a stationary manner in the housing (20).

12. Flour mill according to any of the preceding claims, characterised in that the axis of rotation (lM) of the motor (30) coincides with the longitudinal axis (lG) of the housing (20).

13. Flour mill according to any of the preceding claims, characterised in that a funnel (25) is arranged on the insertion opening (24).

14. Flour mill according to any of the preceding claims, characterised in that a downpipe (27) is arranged in the housing (20), which pipe reaches in particular from the cover part (23) at least to an adapter (71).

15. Flour mill according to any of the preceding claims, characterised in that a removal opening (29a) is arranged on the housing (20), in particular between the rotor (40) and the cover part (23), in particular in an upper mill housing (29).