METERING AND/OR WEIGHING DEVICE FOR FOODSTUFF

Abstract

A metering and/or weighing device includes a bulk material container with a bulk material inlet and a bulk material delivery. The latter is configured to deliver bulk material which is present in the bulk material container, in intervals in a metered and/or controlled manner. The metering and/or weighing device has a radar sensor which is attached to the container at the upper side and generates a beam cone which is directed downwards into an inside of the container, in order to determine a level of the bulk material which is present in the container.

Claims

1. A metering and/or weighing device for foodstuff products which are present as bulk material, with a container with a bulk material inlet for feeding bulk material into the container and with a bulk material delivery which is configured to deliver bulk material which is present in the container, in intervals in a metered and/or controlled manner, wherein a radar sensor which is attached to the container at the upper side and generates a beam cone which is directed downwards into an inside of the container, in order to determine a level of the bulk material which is present in the container.

2. The metering and/or weighing device according to claim 1, wherein the radar sensor comprises a radar sensor module with a radio wave transmitter and a radio wave receiver as well as a convergent lens, wherein the lens is arranged at a distance to the radar sensor module in order to bundle radio radiation which is emitted by the radio wave transmitter.

3. The metering and/or weighing device according to claim 1, wherein an opening angle () of the beam cone is between 5 and 15.

4. The metering and/or weighing device according to claim 1, wherein the bulk material delivery comprises a control element which comprises a feed roller or an electrically or pneumatically actuatable shut-off element.

5. The metering and/or weighing device according to claim 1, wherein a distance between the radar sensor and the bulk material delivery is between 0.1 m and 3 m.

6. The metering and/or weighing device according to claim 1, being a feed of a roller mill and comprising a feed roller, through which feed roller a meterable quantity of a cereal product can be delivered to a cereal product processing unit of the roller mill which is arranged downstream.

7. The metering and/or weighing device according to claim 1, further comprising a weighing unit with a load cell for determining a weight of the bulk material which is contained in the container.

8. The metering and/or weighing device according to claim 7, which is configured to determine a density of the bulk material from the determined level as well as the determined weight.

9. The metering and/or weighing device according to claim 7, which is a bulk scale or a differential scale for bulk material.

10. A roller mill comprising a processing unit with at least one pair of rollers between which a cereal product is reduced in size and/or pressed, as well as the metering and/or weighing device according to claim 6 for metering a feed of the cereal product to the processing unit.

11. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Embodiment examples of the invention are hereinafter described by way of drawings. In the drawings, the same reference numerals denote equal or analogous elements. The drawings are all schematic. In part, they show elements which partly correspond to one another, in sizes which vary from figure to figure. There are shown in:

[0036] FIG. 1 a view of a roller mill;

[0037] FIG. 2 a cross section through a feed of roller mill;

[0038] FIG. 3 a radar sensor;

[0039] FIG. 4 a cross section through a bulk scale; and

[0040] FIG. 5 a cross section through a differential scale.

DETAILED DESCRIPTION OF THE INVENTION

[0041] FIG. 1 shows a roller mill 1 as is used in cereal mills. The roller mill includes at least one housing, in which at least one pair, often several pairs, of rollers is/are arranged. The cereal product which is brought in from above is reduced in size and/or pressed between the rollers of the roller pair. For the purpose of feeding a metered quantity of the cereal product, the roller mill includes a feed 3 which is designed as a device according to the invention.

[0042] The feed 3 which is represented schematically in cross section (section plane perpendicular to the picture plane of FIG. 1) in FIG. 2 includes a bulk material container 40 with a bulk material inlet 11 as well as a bulk material delivery. The latter is formed by a feed roller 41 and a feed slide 43 which is movable relative to the feed roller by way of a suitable mechanism 44, and between which a feed gap 42 forms, through which gap the bulk material 20 is transported onwards by the at least one roller pair for the purpose of processing. The possibility of the inside of an upper part of the container 40 being able to be viewed from the outside through a viewing window 49 is illustrated in FIG. 1.

[0043] The radar sensor 31, specifically a pulsed coherent radar sensor is assembled on the container 40 at the upper side. It generates a beam cone 33 of radio wave radiation which is directed downwards onto the (free) surface 21 of the bulk material 20 and detects radiation which is reflected by the surface 21. The time-of-flight of the radio wave radiation to the surface and back to the sensor can be determined by way of the measurement of the reflected radiation. Double the distance between the radar sensor 31 and the surface 21, and herewith the level 22, thus the degree of filling results directly from the time-of-flight.

[0044] The applied radio wave radiation can have a comparatively short wavelength corresponding to a frequency of for example above 50 GHz, for example roughly 60 GHz. In particular, the radio waves are consequently microwaves as are characteristic for radar technology. In radar technology, the applied microwaves are sometimes also called radar waves. Within the possible spectrum of radar waves, in the present context it is relatively short-waved radar waves with frequencies above 20 GHZ, in particular above 50 GHz and for example as mentioned roughly 60 GHz which are of interest.

[0045] The measurement value for the filling level (level 22) which is determined by the radar sensor 31 is transferred to a control module 45. This control module 45 can form the control of the complete roller mill 1 or be an independent control module of the feed 3. In particular, it can communicate directly or indirectly with other units of a facility, to which the roller mill belongs, in order for example to influence the feed of the cereal product to the roller mill. The feed slide 43, the feed roller 41 and/or further elements of the feed which are not shown in FIG. 2, for example a conveying screw for the horizontal distribution of the cereal product can also be controlled by the control module 45.

[0046] The radar sensor 31 which is also represented in FIG. 3 includes a radar sensor module 32 with one or more integrated circuits, for example on a circuit board. The radar sensor module includes, under certain circumstances in an integrated manner, a transmitter and a receiver as well as evaluation electronics. Furthermore, the radar sensor 31 includes a carrier structure with a lens holder 34 as well as a convergent lens 35 for bundling the emitted radio radiation. The lens can be manufactured for example from a plastic and under certain circumstances it can be created in a tailored manner with a method of additive manufacturing technology (3D-printing).

[0047] The lens 35or very generally bundling optics of the radar sensorin particular can be designed such that the opening angle of the beam cone is between 5 and 15, in particular between 6 and 12, for example roughly 8. It has been found that opening angles in this range result in an effect which is optimised for the applications which are described in this text. On the one hand, given a larger opening angle, the scatter effect of the vessel walls would be significant, and the signal would be averaged over too large a region of the surface 21 and therefore be fuzzy. On the other hand, given smaller opening angles, the radio power would have to be greatly reduced so that too high, potentially harmful radiation powers do not result. A reduction of the radio power, however, would have a negative effect on the signal quality.

[0048] FIG. 4 shows an example of a further metering and/or weighing device, specifically a bulk scale 61 for cereal products and other foodstuff products which are present as bulk material. The bulk scale likewise includes a container 40 and a bulk material inlet 11. Furthermore, it is equipped to measure a weight of the bulk material which is present in the inside of the container. For this purpose, it includes at least one load cell 64 which either measures the weight of the complete container 40 with the contents, from which the weight of the bulk material 20 can be determined whilst taking into account calibration data, or which can alternatively also measure the weight force which bears on an element in the inside of the container, for example on an outlet flap 63.

[0049] As is known per se for bulk scales, the bulk material is admitted through the bulk material inlet 11 in portions, which is why for example an inlet flap (not drawn in FIG. 4) can be present and which can open and close the bulk material inlet in a controlled manner by way of a control module 45. The weight measurement takes place when no bulk material is fed and the outlet flap 63 is closed. The outlet flap 63 is opened subsequently to the measurement and the container is thus emptied by way of the bulk material getting into an outlet region 65, from which it can continuously flow away.

[0050] Similarly to the aforedescribed feed 3 for a roller mill 1, the radar sensor 31 serves for determining the distance to the surface 21 of the bulk material and herewith for determining the filling level. The information on the filling level which is determined in such a manner can firstly very generally be used for the control of the processes. For example, one can ensure that the container is not overfilled at any point in time, which could adulterate measurements and possibly block elements.

[0051] Secondly, in particular one can envisage the control module 45 effecting a measurement being carried out by the radar sensor when (also when or only when) no bulk material is fed and the outlet flap 63 is closed. The filling level is then a measure for the volume of the bulk material whose weight is measured. From this, the density of the bulk material can be determined in an approximate manner. Although the volume measurement is generally significantly less precise in comparison to the weight measurement, since the exact course of the surface 21 is not taken into account and cannot even be determined with a single radar sensor, even an approximate evaluation of the bulk material density however is also valuable and despite this can be used for the control of the bulk material quantity which is respectively fed to the scale. A value for the density can also represent valuable information for other devices of a facility to which the determined value can be provided. By way of this, in contrast to the state of the art, for example control procedures and manual adjustments by an operator can be spared, for example if one changes between different types of processed bulk material (for example between grains, flour, semolina, coarse meal, different cereal types, etc).

[0052] FIG. 5 shows a further bulk material scale, specifically a differential scale 71. In contrast to the bulk scale 61 of FIG. 4, the bringing-out of the bulk material is not effected in intervals in an intermittent manner, but through an outlet flap 73 with a controllable throughput. With this scale too, the weight in the container is measured and the weight which flows out of the container 40 per unit of time is also determined, in particular during which no feed of bulk material is effected. This can be used for the closed-loop control of the throughput through the outlet flap 73. The function of the radar sensor 31 is analogous to the bulk scale 61 according to FIG. 4.