Abstract
A sensor system and a method for optical analysis of bulk material, having a sample space for receiving the bulk material that is to be examined, wherein a measurement section extending in the bulk material is realized in the sample space. In this case, means for changing the length of the measurement section are present. A harvester equipped, a laboratory or mobile system equipped with the system is also provided.
Claims
1. A sensor system for optical analysis of bulk material, the sensor system comprising: a sample space to receive the bulk material that is to be examined; a measurement section extending in the bulk material, the measurement section formed in part in the sample space; and an eccentric unit to change a length of the measurement section are present.
2. The sensor system as claimed in claim 1, wherein the eccentric unit comprises at least one eccentric housing arranged on an eccentric, having a passage window for measurement radiation, which eccentric housing, upon rotation of the eccentric, performs a movement having one component along the measurement section.
3. The sensor system as claimed in claim 1, further comprising an element that is arranged on a sensor housing and is adapted to move a passage window for measurement radiation in purely translational fashion.
4. The sensor system as claimed in claim 3, wherein the element is an axially displaceable cylinder that is provided at an end side with the passage window for the measurement radiation.
5. The sensor system as claimed in claim 3, wherein the element or a cylinder is arranged in a U-shaped structure, and wherein the passage window is situated opposite an inner side of one of the legs of the U-shaped structure.
6. The sensor system as claimed in claim 5, further comprising a further passage window for a measurement radiation or an element that at least partially reflects the measurement radiation is arranged on the inner side of the leg of the U-shaped structure.
7. The sensor system as claimed in claim 3, comprising at least one strut connected to the sensor housing, on which a holder is arranged, wherein an entrance window for the measurement radiation or an element that at least partially reflects the measurement radiation is arranged on the holder.
8. The sensor system as claimed in claim 1, further comprising a feeder for continuously or quasi-continuously feeding the bulk material that is to be examined to the sample space or for removing bulk material from the sample space are present.
9. A harvester having a sensor system as claimed in claim 1.
10. The harvester as claimed in claim 9, wherein the harvester is a combine harvester.
11. The harvester as claimed in claim 10, wherein the sample space is arranged in a region between a threshing unit and a grain tank of the combine.
12. A method for optical analysis of bulk material, the method comprising: feeding bulk material to be examined into a sample space; guiding electromagnetic radiation through a measurement section of variable length, which extends in the bulk material that is situated in the sample space, during an individual measurement period; evaluating the measurement radiation received by a receiver unit during the individual measurement period; and removing the bulk material from the sample space.
13. The method as claimed in claim 12, wherein the feeding or removing of bulk material into or from the sample space is controlled such that the bulk material rests in the region of the measurement section during an individual measurement period.
14. The method as claimed in claim 12, wherein the feeding or removing of bulk material into or from the sample space is controlled such that the bulk material is moving in the region of the measurement section during an individual measurement period.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein:
[0024] FIG. 1 schematically illustrates process components during the transport of bulk material;
[0025] FIG. 2a shows a perspective view of an embodiment of the apparatus according to the invention in a first configuration;
[0026] FIG. 2b shows a perspective view of the apparatus according to the invention in a second configuration;
[0027] FIG. 3 shows a cross-section view of an embodiment of the apparatus according to the invention;
[0028] FIG. 4 shows in a cross-section view, an of the apparatus according to the invention; and
[0029] FIG. 5 shows in a cross-section view an embodiment of the apparatus according to the invention.
DETAILED DESCRIPTION
[0030] FIG. 1 shows a schematic illustration of process components during the transport of bulk material across a measurement box 1, in an superordinate apparatus, in which the present invention can be realized. The sample space is here realized by the measurement box 1. The inflow of the bulk material into the measurement box 1 is here indicated by way of the arrow 3. The arrangement shown can be realized in a combine, in which case the bulk material 2 can be in particular threshed cereal, corn or beans. The bulk material 2 is in this instance transported from a threshing unit (not illustrated in the figure) into the measurement box 1 and is subsequently conveyed, using an auger 4, which is typically also referred to as an elevator, into a grain tank (not illustrated), as is indicated by the arrow 5.
[0031] Integrated in the measurement box 1 is a fill level sensor unit 6, which can read the height of the bulk material 2. The fill level sensor unit 6 is flange-mounted to the measurement box 1 as a component and for that reason can be removed, exchanged and serviced with little outlay. For a correct measurement function, a minimum height of the bulk material 2 in the measurement box 1 is necessary. This is ensured by a drive controller of the auger 4, which transports the bulk material 2 as desired into the grain tank. An empty measurement box 1 is necessary only for the calibration of the fill level sensor unit 6.
[0032] FIG. 2a shows a perspective view of a first embodiment of the sensor system according to the invention in a first configuration. The sensor system here shows two exchangeable beam guidance units 7 and 8, which are flange-mounted to the measurement box 1 and can be used to perform an optical measurement of the bulk material by way of a settable layer thickness. A first deflection unit 73 and a second deflection unit 83 are fixed in their relative positions with respect to the measurement box 1 and each passes through a cut-out in the eccentric 72 and 82, respectively, arranged on which, to change the measurement section, are respective eccentric housings 71 and 81, which project into the measurement box 1. The eccentric housings 71 and 81 are provided here with an exit window 74 and respectively an entrance window 84, through which the measurement radiation can pass in each case during operation of the system. During measurement operation, measurement radiation is coupled in via the first deflection unit 73, is subsequently redirected at the first deflection mirror 731, passes through the exit window 74 and, after it has passed through the bulk material that is to be analyzed typically by way of transreflection, passes via the entrance window 84 and the deflection mirror 831 to a receiver (not illustrated in the figure) for further analysis. Via a rotation of one or both eccentrics 72 and 82, the distance between the two passage windows 74 and 84 can be set. The distance and the orientation of the two deflection units 73 and 83 remains unchanged in this case; however, the layer thickness of the bulk material 2 that is to be analyzed changes.
[0033] FIG. 2b shows, likewise in a perspective view, the described embodiment of the invention in a changed rotational position of the eccentrics 72 and 82 with respect to one another. It is clear that, owing to the rotation of the eccentrics, the layer thickness and consequently the path length travelled by the beam through the bulk material 2 has decreased. The variation of the layer thickness is in particular advantageous in order to optimize the measurement for different types, sizes and structures of the bulk material 2.
[0034] FIG. 3 shows an alternative embodiment of the invention. In the variant shown in FIG. 3, it is only necessary to attach a housing to the measurement box 1. The flange-mounted sensor housing is realized as a U-system housing 11. To change the measurement section, a displaceable cylinder 12 can be provided, in which the exit window 74.3 for the measurement radiation is arranged and via which the layer thickness can be set. The beam passes through the bulk material 2 and arrives, due to the U structure of the housing 11, at an opposite entrance window 84.3, from where it is guided through the U-structure out of the measurement box and to a receiver (not illustrated), as is indicated by the dashed beam path. An advantage of the shown U system is that the measurement radiation is guided completely in an apparatus which can be guided into the measurement box from one side, with the result that the complete sensor arrangement can be installed in one installation step for example in a vehicle. One advantage of the shown arrangement for transreflection measurements is that, for example, in the case of a reference measurement, the two windows which are in contact with the medium are also taken into account. Moreover, a transreflection measurement makes possible the use of silicon detectors which are available on the market in a wide variety of configurations.
[0035] FIG. 4 shows a third embodiment of the invention. The sensor system is depicted here also with a flange-mounted housing 11.4. The variable layer thickness can be set by way of the displaceable cylinder 12.4 in which the exit window 74.4 for the measurement radiation is arranged. Attached to the housing 11.4 are two struts 13 and 14, at which an entrance window 84.4 for the measurement radiation is arranged by way of a holder 15. The measurement radiation passes through the bulk material 2 and the entrance window 84.4 and arrives, through the strut 14 having a hollow design, at a receiver (not illustrated in the figure).
[0036] FIG. 5 shows a fourth embodiment of the invention. In contrast to the third variant, a transparent plate 15.5 is attached, as a holder, to the struts 13.5 and 14.5. Arranged thereon, opposite the passage window of the measurement radiation 74.5 on the displaceable cylinder 12.5, is a concave mirror 16. The measurement radiation is coupled out of the passage window 74.5, passes through the bulk material 2, and travels through the transparent plate 15.5 to arrive at the concave mirror 16, where it is reflected back. The measurement radiation consequently travels along the path through the bulk material 2 twice and arrives back at the passage window 74.5, from where it is guided to a receiver.
[0037] The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims:
