Distribution metering device for a roller mill, roller mill with such a distribution metering device, method for grinding grinding stock, and roller mill comprising a switching cabinet with a cooling system

Abstract

A distribution metering device (I) for a roller mill which includes a housing (2) with at least one grinding stock inlet (3), at least one grinding stock outlet (4), and a feed roll (5) which is arranged in the housing (2) for metering grinding stock into a grinding gap of the roller mill through the grinding stock outlet (4). The feed roll is rotatable about a feed roll axis (SA). A conveyor shaft (6) is arranged in the housing (2) for distributing grinding stock along the feed roll (5). The conveyor shaft is rotatable about a conveyor shaft axis (FA). The conveyor shaft axis (FA) is substantially parallel to the feed roll axis (SA), and a first fill state sensor (7) is arranged in the housing (2) for ascertaining a first grinding stock fill state of the housing (2).

Claims

1. A distributing and metering device (1) for a roller mill comprising: a housing (2) having at least one milling-material inlet (3) and at least one milling-material outlet (4), a feeding roller (5), which is arranged in the housing (2), for metering milling material into a milling gap of the roller mill through the milling-material outlet (4), which roller is rotatable about a feeding roller axis (SA), a conveying shaft (6), which is arranged in the housing (2), for distributing milling material along the feeding roller (5), which shaft is rotatable about a conveying shaft axis (FA), wherein the conveying shaft axis (FA) is arranged parallel to the feeding roller axis (SA), and a first filling level sensor (7), which is arranged in the housing (2), for determining a first milling-material filling level of the housing (2), the distributing and metering device (1) further comprises: a second filling level sensor (8), which is arranged in the housing, for determining a second milling-material filling level of the housing (2), the milling-material inlet (3) and the first filling level sensor (7) are arranged at a first third of the feeding roller (5) and of the conveying shaft (6), and the second filling level sensor (8) is arranged at a last third of the feeding roller (5) and of the conveying shaft (6).

2. The distributing and metering device (1) according to claim 1, wherein that a rotational speed of the feeding roller (5) is controlled or regulated independently of the conveying shaft (6) and in dependence on the first and/or second milling-material filling level.

3. The distributing and metering device (1) according to claim 1 wherein that a rotational speed of the conveying shaft (6) is controlled or regulated independently of the feeding roller (5) and in dependence on the first and/or second milling-material filling level.

4. The distributing and metering device (1) according to claim 1, wherein that the milling-material outlet (4) is designed as a gap (9) between the feeding roller (5) and a throttle device (10).

5. The distributing and metering device (1) according to claim 4, wherein the throttle device (10) comprises a rotatable profile (11) with a circular segment-shaped cross section.

6. The distributing and metering device (1) according to claim 4, wherein a gap width of the gap (9) is controlled or regulated independently of the feeding roller (5) and/or of the conveying shaft (6) and in dependence on the first and/or second milling-material filling level.

7. The distributing and metering device (1) according to claim 1, wherein the distributing and metering device (1) further comprises a guiding arrangement (18) for guiding milling material to the feeding roller (5), the guiding arrangement ends with an edge (19) which is arranged in such a way that no dead zone is formed below the feeding roller (5) that cannot be completely emptied during operation, by the edge being arranged at a distance from the feeding roller of between 0.001 and 5 mm.

8. The distributing and metering device according to claim 7, wherein, in a radial section through the feeding roller, the edge is arranged with an angular distance between 0° and 90° with respect to a perpendicular through the feeding roller axis.

9. A roller mill (14) having at least two rollers which define a roller gap, wherein the roller mill further comprises the distributing and metering device (1) according to claim 1.

10. A method for the milling of milling material in a roller mill, comprising the step of feeding the milling material to the roller mill via a distributing and metering device (1) according to claim 1.

11. The method according to claim 10, wherein a rotational speed of the feeding roller (5) is controlled or regulated in dependence on the first milling-material filling level.

12. The method according to claim 11, wherein the rotational speed of the feeding roller (5) is adapted to be proportional to a deviation between a desired value of the first milling-material filling level and the actual value of the first milling-material filling level.

13. The method according to claim 10, wherein a rotational speed of the conveying shaft (6) is controlled or regulated in dependence on the second milling-material filling level.

14. The method according to claim 13, wherein the rotational speed of the conveying shaft (6) is adapted to be inversely proportional to a deviation between a desired value of the second milling-material filling level and the actual value of the second milling-material filling level.

15. The method according to claim 10, carried out by a device having the milling-material outlet (4) designed as a gap (9) between the feeding roller (5) and a throttle device (10), and a gap width of the gap (9) is controlled or regulated in dependence on the first milling-material filling level.

Description

(1) The invention will be better described below on the basis of a preferred exemplary embodiment in conjunction with the figures, in which:

(2) FIG. 1 shows a schematic sectional view of the distributing and metering device according to the invention in a plane parallel to the feeding roller shaft;

(3) FIG. 2 shows a schematic sectional view of the distributing and metering device according to the invention in a plane perpendicular to the feeding roller shaft; and

(4) FIG. 3 shows a schematic perspective view of the roller mill according to the invention with a distributing and metering device and a switching cabinet.

(5) FIGS. 1 and 2 schematically illustrate a distributing and metering device 1. The distributing and metering device 1 comprises a housing 2 having a milling-material inlet 3 and a milling-material outlet 4. In the housing 2 there are arranged a feeding roller 5, which can be rotated about a feeding roller axis SA, and, above the feeding roller 5 in the milling-material flow direction, a conveying shaft 6. The conveying shaft in this case takes the form of a screw conveyor and can be rotated about the conveying shaft axis FA, which is parallel to the feeding roller axis SA. To drive the feeding roller 5 and the conveying shaft 6, respective motors 15 and 16 are present. The motors 15 and 16 are operatively connected to a control unit 12 (schematically illustrated by the dashed line).

(6) In the housing 2 there are arranged two filling level sensors 7 and 8 which are designed to determine the milling-material filling level in the housing and are likewise operatively connected to the control unit 12.

(7) The first filling level sensor 7 is arranged in the region of the milling-material inlet 3 at a first end of the feeding roller 5 and of the conveying shaft 6. The second filling level sensor 8 is arranged at the other end of the feeding roller 5 and of the conveying shaft 6. Two filling level sensors 7 and 8 are thus arranged at the two ends of the feeding roller 5 and of the conveying shaft 6. The milling-material inlet 3 is likewise situated not centrally as in the case of known devices, but is arranged above the first end of the feeding roller 5 and of the conveying shaft 6.

(8) In FIG. 2 there can also be seen the construction of a throttle device 10 which is used for setting a gap 9 which serves as a milling-material outlet 4 of the housing 2. The throttle device 10 comprises, in addition to actuators and bearings, an elongate profile 11 with a circular segment-shaped cross section. Rotating the profile 11 (schematically illustrated by the dashed position) allows the gap width of the gap 9 to be set.

(9) Also visible in FIG. 2 is the arrangement of the guiding arrangement 18 which takes the form of a chute. The guiding arrangement ends with an edge 19 close to the surface of the feeding roller 5. The edge 19 is arranged such that no milling material can pass under the feeding roller 5 or no milling material can remain in the feeding space; for example, the edge 19 can for this purpose be arranged at an angular distance of 0° to 90° with respect to a perpendicular through the feeding roller axis SA. This arrangement reduces any dead space around the feeding roller and facilitates residue emptying/cleaning of the distributing and metering device 1. A shroud 20 adjoins the edge 19 for sealing purposes. In the prior art, the feeding space encloses the feeding roller (discharge roller) for the most part, with the result that a dead zone is formed below the feeding roller (discharge roller) that cannot be completely emptied during operation and would thus have to be cleaned manually at a standstill. This dead zone can be an unwanted home for insects etc. Given the arrangement of the edge 19, it should therefore ideally be ensured that no such dead zone can form.

(10) During operation of the distributing and metering device 1, milling material is supplied through the milling-material inlet 3. Rotation of the conveying shaft 6 causes the milling material to be conveyed from the first end in the direction of the second end of the feeding roller 6. This distribution is monitored by the second filling level sensor 8. If the second milling-material filling level (actual value) measured by the second filling level sensor 8 deviates from a desired value of the second milling-material filling level, the rotational speed of the conveying shaft 6 is correspondingly adapted such that more or less milling material is conveyed to the other end of the feeding roller 5.

(11) The feeding roller 5 is driven at the same time. If the first milling-material filling level (actual value) measured by the first filling level sensor 7 deviates from a desired value of the first milling-material filling level, the rotational speed of the feeding roller 5 is correspondingly adapted such that more or less milling material is discharged to ensure that the filling height of the housing remains constant.

(12) In FIG. 3 there can be seen a roller mill 14 having a distributing and metering device 1. Emphasis should be placed on the switching cabinet 13 which is arranged on the roller mill and which accommodates the control unit 12 and is cooled by Peltier elements 17 (of which only cooling ribs are visible). Other ATEX-compliant cooling systems are also conceivable, for example liquid cooling systems, in particular water cooling systems; ATEX-compliant fans; etc.