METHOD AND DEVICE FOR PRODUCING SEED-LIKE SOLID PARTICLES AND COMPUTER PROGRAM

Abstract

The invention relates to a method for producing seed-like solid particles from at least one, but typically two starting substances, wherein the produced particles are optically detected by means of an optical detection system, wherein data of the produced particles detected optically by the optical detection system is provided, and at least one, but typically two parameters of the produced particles are determined from the optically detected data of the produced particles, wherein at least one, but typically two optically determined parameters automatically synergetically influence the production process of further particles on the basis of the optically detected data of the produced particles. The invention further relates to a device for carrying out the method and a computer program for carrying out the method.

Claims

1. A method for producing granular solid particles, the method comprising: producing granular solid particles from at least one starting substance by a production process; optically capturing the produced granular solid particles using an optical capturing system to produce data; determining at least one parametric quantity of the produced granular solid particles from the data; and automatically influencing at least one parameter of the production process on the basis of the at least one parametric quantity, wherein the at least one parametric quantity is a grain size or a grain size distribution of the produced granular solid particles or a variable ascertained therefrom.

2. The method of claim 1, further comprising: specifying a target value for the at least one parametric quantity; and producing additional particles by a feedback control of the production process after the influencing, wherein the additional particles have a parametric quantity that substantially corresponds to the target value.

3. The method of claim 2, wherein the feedback control is carried out at least by means of a primary feedback control parameter, and wherein the primary feedback control parameter is the grain size or the grain size distribution of the produced granular solid particles or a variable ascertained therefrom.

4. The method of claim 2, wherein the feedback control is carried out at least by means of a primary feedback control parameter and a secondary feedback control parameter, wherein the primary feedback control parameter has priority over the secondary feedback control parameter.

5. The method of claim 4, wherein the secondary feedback control parameter is at least one selected from the group consisting of a number of particles, a temporal change in a number of particles per unit time, and a variable ascertained therefrom.

6. The method of claim 1, wherein the produced granular solid particles are produced from at least a first and a second starting substance, which differs from the first, and wherein the at least one parameter of the production process is selected from the group consisting of a mixing ratio between the first and the second starting substance, an addition of the first starting substance to the production process, and an addition of the second starting substance to the production process.

7. The method of claim 1, wherein the produced granular solid particles are optically captured by at least one camera of the optical capturing system.

8. The method of claim 1, wherein the produced granular solid particles are illuminated by a light source of the optical capturing system during optical capturing using an incident-light method.

9. A device for producing granular solid particles by the method of claim 1, the device comprising: at least one first starting substance feed device, at least one processing device for processing the at least one starting substance, and at least one optical capturing system which is configured for optically capturing the produced granular solid particles produced emerging from the processing device, and at least one control device which is configured to control at least one parameter of the production process, the at least one parameter depending on at least one parametric quantity ascertained by the optical capturing system.

10. The device of claim 9, wherein the device has at least one second starting substance feed device for a second starting substance, wherein the at least one second starting substance feed device has a valve arrangement with a plurality of switchable valves arranged in parallel branches, and wherein the at least one second starting substance is fed to the processing device with varying quantities depending on the valve actuation of the valves.

11. The device of claim 9, wherein the at least one first starting substance feed device has a valve arrangement with a plurality of switchable valves arranged in parallel branches, and wherein the at least one first starting substance is fed to the processing device with varying quantities depending on the valve actuation of the valves.

12. The method of claim 1, wherein the method is carried out by executing a computer program on a computer, wherein the computer program has a program code means.

Description

[0024] In the drawings FIG. 1 shows a schematic illustration of a device for producing granular solid particles and

[0025] FIG. 2 is a flowchart of a sequence during the optical data capturing and

[0026] FIG. 3 shows image data generated in the course of the sequence of FIG. 2 and

[0027] FIG. 4 shows a process of the feedback control of the at least one parameter of the production process in a time diagram.

[0028] The device illustrated in FIG. 1 has a first starting substance feed device 1, 3. The latter includes a storage container 1, in which a supply of a first starting substance 2 of the production process is present, and a conveyor device 3. It is assumed that the first substance 2 has a pulverulent consistency. In order to further convey this pulverulent first starting substance 2, the conveyor device 3for example, a screwis arranged below the storage container 1. The conveyor device 3 conveys a feed stream 4 of the first starting substance 2 to a processing device 12. The processing device 12 can be embodied, for example, as a granulating or pelletizing plate, which is rotated. The rotational movement results in a build-up agglomeration of the fed first starting substance 2, in combination with an additionally fed second starting substance 6. The resulting granular solid particles 14 are fed to a further use via an output device 15, for example a chute or a conveyor belt.

[0029] The device has a second starting substance feed device 5, 7, 9. The latter includes a second storage container 5, in which the, for example liquid, second starting substance 6 is present, and lines 7, 9. The second starting substance 6 is fed to the processing device 12 via the lines 7, 9, for example by spraying the second starting substance 6 from the end of the line 9. The second starting substance 6 can be fed to a further application via a further line 8, for example for introducing it into a mixer.

[0030] The device furthermore has a control device 18, for example in the form of an electronic control device. The electronic control device can be implemented substantially by a computer, possibly supplemented by corresponding hardware expansions for interfaces to the components that will be explained below.

[0031] The control device 18 is connected to a flow meter 11. The mass flow of the feed stream 4 can be measured by way of the flow meter 11. The control device 18 is additionally connected to an optical capturing system 16, 17.

[0032] The optical capturing system has a camera 16, which is directed at the particles 14 to record them and to output corresponding images to the control device 18. In order to improve the quality of the recordings of the camera 16, the particles 14 are illuminated by light sources 17.

[0033] A valve arrangement 10 through which the amount of the second starting substance 6 that is sprayed out of the line 9 can be influenced is furthermore arranged in the line 9. The valve arrangement 10 can, for example, have a plurality of switchable valves arranged in parallel branches, so that the discharge of the second starting substance 6 can be switched off completely or can be set to different strengths by optionally switching one or more of said valves on or off.

[0034] The control device 18 reads the data that are output by the flow meter 11 and the image data that are output by the camera 16 and processes them. As part of this processing, the control device 18 generates control data for the valve arrangement 10. The at least one parameter of the production process of further particles 14 is influenced by way of the valve arrangement 10 and the corresponding control data, and the previously explained feedback control process is implemented in this way, which will be explained in more detail below with reference to the further figures.

[0035] FIG. 2 shows the processing of the images of the camera 16 in the control device 18, for example in the form of a computer program, wherein the at least one parametric quantity of the particles 14 produced is determined from the optically captured data of the particles 14 produced. This parametric quantity is then used for further feedback control.

[0036] The computer program is initialized in a step 20. In a subsequent step 21, the camera 16 is initialized. The program sequence is determined in a step 22. This additionally includes a waiting loop, which is carried out, for example, when it is necessary to wait for new output data during the image processing.

[0037] In a step 23, which follows step 22, the camera image is first checked with respect to brightness and coverage. This is an initial plausibility check of the image data. An image conversion and a calibration of the optical capturing system are then carried out in step 24, that is to say the size scale is determined. This step 24 needs to be carried out once to set up the optical capturing system. In a subsequent step 25, further image adjustments can be made, for example pre-filtering (blur/sharp). This step is optional. Furthermore, a white/brightness adjustment should be carried out once. In a subsequent step 26, a black-and-white threshold value is defined. An image section that is to be processed is defined. In a subsequent step 27, the smallest particles in the image data are filtered out. Additional segmentation of the image data can take place. Step 27 is likewise optional.

[0038] An algorithm is then carried out in step 28 for segmentation. Segmentation means that the individual particles are automatically detected in the camera image by the algorithm mentioned, even if they partially overlap during the image recording of the camera 16. In step 29, for example, the segmentation can be carried out by calculating a distance map. The calculation can be carried out according to Danielsson's method or the standard method. Alternatively, segmentation can be carried out in step 30 using a blur filter with edge preservation. It is also possible to carry out both segmentation algorithms and then to overlay or combine the data generated in the process.

[0039] In a subsequent step 31, a watershed analysis is carried out. The data generated in the process are combined in a subsequent step 32 with the data generated in step 26 or in step 27, for example by means of pixel-wise multiplication. In a subsequent step 33, an overlay image is created in which the image data generated in step 26 are overlaid with the image data generated in step 32. This step serves merely to better illustrate the process result and is usually deactivated to optimize the computing time. In a subsequent step 34, parametric quantities of the particles 14 are determined from the image data now generated, for example the grain size or grain size distribution thereof, in particular the d.sub.50 value or another suitable percentile of the grain distribution.

[0040] In a subsequent step 35, further permeability values and/or average values can be determined. In a subsequent step 36, the data of the feed stream 4 are read from the optionally usable flow meter 11.

[0041] In subsequent steps 37 and 38, the data obtained in this way are prepared. The generated data and the images of the camera 16 can be stored in a step 39. The method then continues with step 22.

[0042] FIG. 3 shows exemplary image data before and after being processed based on the numerical identifiers specified in some of the steps in FIG. 2.

[0043] The multiplication symbols symbolize the combination of the data in step 32. As can be seen, the segmentation enables the individual captured particles to be separated very well in the image data, with the result that particles arranged very close together in the image are not recognized as a single large particle, but can instead be automatically recognized and evaluated as individual particles.

[0044] The data obtained in steps 34 and 35, which are based on the optically captured data of the particles produced, are now used to influence at least one parameter of the production process, that is to say in this case to control the valves of the valve arrangement 10. This can be done for example in the manner shown in FIG. 4.

[0045] FIG. 4 shows the d.sub.50 values of the particles 14 in the curve profile 40 and the number of particles per unit time in the curve profile 41. The particles 14 produced are to be produced with a particle size of, for example, 3.5 mm (d.sub.50 value). This is thus a target value for the feedback control. Since this target value cannot be adhered to exactly during the production process, tolerances are permitted. Based on this, specific threshold values 50, 51, 53, 54 with respect to the d.sub.50 values (curve profile 40) are defined for carrying out the feedback control and in particular for controlling the valve arrangement 10. Control patterns for the valves of the valve arrangement are ascertained depending on whether the d.sub.50 value exceeds or falls below specific threshold values.

[0046] If, for example, Kieserit-M or Kieserit-E or a mixture of the two is used as the first starting substance in the production process and an MgSO.sub.4 solution is used as the second starting substance, a larger amount of the second starting substance 6 must be fed in during the feedback control process if the d.sub.50 value is too low than is required if the d.sub.50 value is in the desired range. If the d.sub.50 value increases too much, the feed of the second starting substance 6 must be reduced or be switched off completely.

[0047] In the sequence according to FIG. 4, the desired range is the range between the threshold values 51 and 53. If the d.sub.50 value is in this range, normal operation, as it is known, is taking place. In this case, an amount of the second starting substance 6 that is assigned to normal operation is discharged via the line 9 and the valve arrangement 10. If the threshold value 51 is exceeded, the feed of the second starting substance 6 is reduced for a first time. If the threshold value 50 is exceeded, the feed of the second starting substance 6 is reduced even more or the feed is switched off. If the value falls below the threshold value 53, the fed amount of the second starting substance 6 is increased. If the value falls below the threshold value 54, the fed amount of the second starting substance 6 is increased still further.

[0048] A further improvement in the feedback control can be achieved by taking the gradient of the curve profile 41 into account. If the curve profile 41 has only relatively short periods of time with increases and decreases in the curve profile or only slight gradients, as for example in the periods 42 and 45, the feedback control based on the primary feedback control parameter d.sub.50 is sufficient. In periods 43, 46 and 48, however, additional intervention is required. This takes place in the form of a positive boost in a way such that a considerable increase in the discharged amount of the second starting substance 6 is set via the valve arrangement 10. A negative boost takes place in the periods 44, 47, that is to say in these periods, the discharged second starting substance is reduced considerably. The time periods for such a negative or positive boost can be limited in the feedback control to a predetermined time limit value, for example to 20 seconds.

[0049] The d.sub.50 values here form the primary feedback control parameter, and the number of particles forms the secondary feedback control parameter. If the corresponding threshold value criteria of the threshold values 50 to 54 occur, the primary feedback control parameter can always overwrite the secondary feedback control parameter, that is to say the primary feedback control parameter has priority in the feedback control in such cases.