DE3448134C2 - - Google Patents

Description

The invention relates to a method for monitoring the Ingredients of flour-like foods according to the preamble of claim 1.

In the grain processing industry has been for some time Infrared spectroscopy for measuring various ingredients or Ingredients (such as protein and water) applied in flour. This content Under infrared light, fabrics have a typical light absorption and Reflection behavior.

Due to natural factors of soil and climate and climate stability are particularly z. B. very much in European and neighboring areas different grain crops a fact. Other areas like e.g. B. The United States, Canada and Australia are regarding cereals production privileged because there are not only fewer climate fluctuations there  occur, but also the soils and the climate best Allow grain qualities in production.

The further processing of the grain in the mill and the bakery faces the task, due to the existing different Cereals to solve optimization tasks, namely with one the largest possible proportion of inexpensive grain (i.e. grain with low protein values etc.) and with the smallest possible proportion of expensive grain (higher protein value, etc.) the best possible flour or to produce bread for customers.

After the offer and price of the cereals on the market strong and subject to rapid changes, it is currently for a mill no longer portable, according to old empirical values of grain mix varieties and add water. Cost considerations as well the needs of the market require constant adaptation to the each existing conditions, what about the use of computers for Determining optimized grain mixes leads.

Extensive reviews of conventional infrared measuring devices to the conclusion that it is probably a pure laboratory measurement of the components of flour-like foods or of food regrinds can successfully make continuous measurements during the ongoing production cannot be regarded as solved.

The handling of laboratory measurements obtained is in one respect very simple: the one possibility is that with one Deviation of the result from reality the measurement in your own or repeated in a foreign laboratory. The other option is there in that the laboratory measurement result is simply ignored and continued to be produced if all other values, including sensory assessment, allow this as responsible. So here stands the man with his Decision in between.

So far, when examining the problem area identified  three "barriers" were shown, which had to be regarded as unsolved:

• 1. A laboratory measuring device can with respect to its components (electronics etc.) may be designed for less severe environmental influences. However, such a laboratory measuring device is used in daily production used, it turns out that the errors caused by environmental factors are not triggered in the vast majority of cases by other faults are separable.
• 2. Is a new system, here infrared spectroscopy, of yours theoretical, especially of their physical, chemical and mathematical side researched and checked in the lab and is the system of daily operational reality that is recognized as being usable subject, there is often a total uselessness immediately for practical suitability in daily use (about nothing explainable errors and deviations whose analysis because of the unexplainable causes cannot take place).
• 3. Representative statements can also be made for larger product quantities due to practical measurements with individual samples usually not with derive sufficient security, so that the current regulation a grinding process depending on the constituents of the material to be ground not considered to be sufficiently resolved during production could be.

From the DE-Z. "The mill and compound feed technology", issue 40, 119th year. from October 7, 1982, pp.550-554 it is known the infrared spectroscopy for the determination of ingredients which the Quality of flour or other food regrind describe, especially for protein and / or water determination to use. In addition to relatively general explanations in this magazine no further details, such as special Information about the mode of operation of the measuring method described regarding the influence of certain factors.

From the DE-Z. "Regulation technology", 1975, volume 3, volume 23, pp. 78-83 it is known to produce the mixture of raw materials of a cement raw meal by regulating the values of the Raw meal components fed to a computer and dependent control parameters for the rule from the computer output signal process can be determined.

In DE-OS 14 98 985 is a device for automatic continuous monitoring of the quality of dry regrind, the regrind continuously flowing from a main line into a tubular one Bypass derived and by means of a continuously driven conveyor in the form of a screw conveyor against the blocking effect at the end a measuring section provided in the closing direction by a Counterweight biased flap is conveyed. Through the Locking effect of the flap and the driving effect of the screw conveyor the measured material introduced into the bypass is initially in a compresses to a certain extent until the pressure of the compressed material overcomes the closing pressure of the butterfly valve and  this opens it. In the area of the bypass there is an infrared measurement line provided on which the regrind introduced into the bypass is continuously running by forced support and in addition to Forced conveyance is compacted, then during this transport the corresponding infrared measurements are made. Here a continuous movement occurs during the measurement on the regrind to be measured, resulting in constant changes in the surface structure that is exposed to the measuring light. The Accuracy of those obtained with an infrared reflectance meter However, measurement results will depend essentially on the surface structure determined on which the infrared light is thrown and from which it enters the Sensor is reflected again. In the known method not only does the location of the individual good bodies change within the range of the measuring light occurring, but by the Movement itself also forms in the slightly compacted good certain flow structures, which result from a complicated interaction between wall friction on the tube walls on the one hand and pressure distribution as well as flow pattern within the compressed On the other hand, the material to be measured results in the tubular measuring section. The occurring time-dependent changes in the to surface to be measured during the measuring phase lead to inaccuracies in the derived measured values, which too still be favored by the fact that at the inlet of the measuring section arranged screw conveyor acting in the longitudinal direction of the measuring section overall to a compression effect with within the measurement range present measurement leads, but nevertheless straight because of the flowing movements and the resulting unsteady states within the measured material pronounced pressure not only differentiate across the cross-section of the measuring tube, but also occur along its longitudinal direction. Hereby there are strongly fluctuating influences on the results of the light reflection measurements to be made on such flowing bulk goods what this known method for the practical use of over monitoring and regulation of certain requirements for the components of the Grist made unsuitable, which is why it is used in industrial practice  evidently has not found an entrance.

Proceeding from this, the object of the invention is this develop the above-mentioned method so that it as a result much more precise determination of the individual components of the measured the ground material for automatic continuous monitoring and adjustment gelation of the components of the regrind also for use in the industrial practice.

According to the invention, this is the case of a method of the type mentioned at the beginning Art achieved in that the forced promotion during each measurement phase exposed to the ground material within the infrared measuring section, then the Grist for the measurements on its irradiation surface by pressure smoothed and in the subsequent measurement that of the compacted meal well reflected light over a computer regarding the reflection intensity of the recorded spectral ranges is evaluated that continues the values determined in this way for the individual components each with a setpoint predefined by another computer and compared in Dependence on the detected deviations Control of process parameters can be derived.

In the claimed invention, the product is easily in the measuring section in front pressed state and then in the area of the sensor for the infrared measurement condenses. The product is light Put pressure so that there are no longer any product cavities are present and the flour always lies smoothly on the sensor, is even lightly pressed against it. But with that are constant Working conditions created, disruptive "boundary conditions" no longer exist, since the compression produces lightly pressed flour within the same and the air can escape. The test sample and the Measurement conditions are optimal and reproducible in every respect, so that the measured values obtained as a suitable starting point for a rule can serve route. With the interruption of forced support a constant flow of material to be measured can be ensured during the measurement phase will. During this time, the entire column of measuring material is at rest 3  up to 30 seconds. After completing the measurement, the whole Product quantity transported away and new product flows, so that the Risk of repeated measurement of the same sample in the area of the Measuring sensor has stuck, is completely switched off.

The method according to the invention takes a decisive step for the regulation in the mill by using not only cavity free and consciously condensed, but also of on his Irradiation surface by pressure-smoothed regrind.

Depending on the application, the measurements can be repeated any number of times, preferably be carried out in a predetermined cycle. It now offers a good way to control and Regulation of the mill with regard to protein and / or water.

There can be one or more real control loops, for example:

• Protein - raw material mix
• Water content - water addition
• Protein - flour mix.

The mill can now be used for the Specification of all values, such as raw material mixture, water addition, Protein content and flour content, etc. At the same time the higher-level computer prescribes limit values within which the mentioned control loops independently the setting of the concerned Check and track operating equipment.

If a control loop protein-raw material mixture is formed, at least partially separate the individual raw material qualities up to of the first grinding, so that a correction is made directly before the Grinding and carried out with the least possible delay can be.

The possibility of water should be used accordingly when adding water  be given immediately before the meal, so at least minor corrections are possible immediately. Major changes in Water must be added in the main preparation before the stand-off cell be made. Of course, when regulating the Protein values like the water values the delays from the milling process be taken into account.

When using the method according to the invention for the Flour composition are the necessary control and To issue redirection commands with regard to the setpoint to be achieved the same applies to adding gluten to flour.

So far, little has been gained on others, gained by the same principle Values such as flour ash and flour color were received. For this too The method according to the invention can be used if the goal of regulating the mill with regard to ash and color values does not attach the same importance as e.g. B. the Regulation of protein and water content.

The test results obtained indicate that actually with the invention another crucial advance for yet another better control and control of the mill as a whole is possible in particular through the possibility of realizing the direct Regulation of protein values and direct regulation of water values.

For reasons of operational safety, it is urgent in almost all cases to repeat the measuring phase cyclically at selectable time intervals. The frequency of repetition depends on the particular one Circumstances of the respective processing process.

Furthermore, it is also expedient if necessary for each individual measurement to be repeated during a measurement phase and especially the measurement results averaged from one group of measurement phases and the second as actual values Computer for controlling or regulating the mixture and / or the To provide water content and / or the flour mixture, and  regulate the product parameters to certain specified values.

The method according to the invention also provides further information a measure of the uniformity of the mill run, whereby from the Comparison of several values on possible sources of interference can be.

The invention is based on the drawing in principle explained for the sake of play. It shows

Figure 1 shows a test pattern corresponding to the prior art.

Fig. 2 shows the same test sample from Fig. 1 after light pressing z. B. in a screw conveyor;

3 schematically shows a test pattern in a compressed state with ge glätteter surface according to the methods of the invention.

Fig. 4 is the ratio of density ρ (kg / cm ³⁾ under varying pressure p (kg / cm ³⁾ in a flour pattern;

Fig. 5 is the schematic view of a measuring apparatus for use in the inventive process it;

FIG. 5a is a section along VV in Fig. 5;

Fig. 6 a to Figure 5, another embodiment of the measuring device with a cushion of air as a means for compression of the material to be measured.

FIG. 6a shows the section VI-VI of Fig. 6;

Fig. 7 shows the principle of a third embodiment of a measuring device used in the inventive method with a spoon as a body;

Fig. 8 is a similar to Figure 5 embodiment with a pneumatic piston, said unit being disposed above a screw conveyor.

Fig. 9 is a schematic view of a further embodiment of a measuring device for use in a method according to the invention, in which the entire measuring device is arranged between a screw conveyor and rear accumulation elements;

Fig. 10 is a schematic plan view of the device of Fig. 9;

FIG. 11A is the schematic representation of a control of the raw material mixture by the inventive method;

FIG. 11B, the schematic representation of an inventive method for controlling the addition of water in Vermahlprozeß, and

Fig. 12 shows the schematic diagram of an inventive method for automatic control of the generation of a mixture of different flour qualities.

Fig. 1 shows a pile 1 with a loose flour directed thereto infrared measurement optics. 2 As can be seen, the material has a large number of gas cavities 3 , so that measurement using infrared rays, according to the method, gives very imprecise results. Both the irregular surface and the uncontrollable air voids falsify the result, since the reflection is influenced by the arbitrary position of the good particles on the surface and the other reacting influencing factors gas or air.

The completely new findings with the invention have now been graphically recorded in FIGS. 2 and 3, the product movement being indicated by arrows 4 and 5 in both solutions with regard to continuous measurement. If the product movement is ensured by forced conveyance, then this leads to a slight pressure as far as it B. brings the screw conveyor with it. In long test runs, all possible sources of error that would have been responsible for the irreversible spread of the measurement results were first searched in vain. The funding, especially in the case of a screw conveyor, can easily be set so that the measuring section is always filled with product. The housing of the screw conveyor was also deliberately chosen so long that the screw-free end was as long as the length of the screw, so that grafting of the product had to be pushed with the screw. The aim was to ensure that the product did not escape from the measuring range and that the packing density could not change during the measurement. Stopping the funding ensured that the measurement sample remained unchanged. Large spreads could not be removed.

The new invention then makes it possible to determine the main sources of interference, as can be seen in FIG. 2. Floury goods have a good air holding capacity. When flour is pressed, the air it contains is also pressed at the same time. By turning off the screw conveyor, not only was the pressure on the flour removed, but the air was also allowed to expand freely. The air was one of the reasons why fine cracks 6 formed on the surface and hollows appeared again in the flour surface facing the infrared measuring optics 2 . The density of the product only appeared to remain the same. Further investigations then led to the finding that the surface of the flour, as it arises through mechanical forced conveyance and a more or less rough inside of the housing, had grooves 7 in the direction of conveyance, depending on the random particle composition, which also interfered with the measurement result impact. This problem could not be solved without additional mechanical intervention and possible venting before the measurement. Due to the considerable compressibility of flour, the sample 8 is not constant in quality without additional intervention. Since the extent in the center area of the graft did not extend to both sides, and the product in the area of the infrared measuring optics 2 was therefore almost immobile, this fact was not recognized for a long time. The product pattern expanded on all sides, as indicated by arrows 9 . The pressure, arrow direction 10 , was largely eliminated.

With the new solution, not only these sources of interference have been eliminated. The new solution provides that controllable pressure media are provided for the measurement of the sample in the compressed state. The forced promotion inevitably results in a certain packing density. This is where the invention comes in, in which an actual compression is produced in the measuring section 24 ( FIG. 5), that is to say in the pre-pressed material, as is expressed in FIG. 3. The measured material 11 is pressed by a piston 12 ' against the measuring optics 2 . Not only is the flour compacted, but at the same time any air pockets that may be present are also eliminated, since the air emerges from the high pressure region 13 . The pressure area 13 is hatched, indicating that an absolutely uniform surface for the purpose of measurement can now be formed and held until the measuring process is complete. The arrows 14 indicate that the flour cannot escape from the pressure area 13 on either side, it is kept under pressure spatially. The higher pressure range effectively has a conical shape and is formed due to the bulk mechanics. When the measurement has ended, the entire material to be measured 11 is pushed away. The new measurement can be repeated at any time or cyclically.

Fig. 4 now shows the pressure and compression behavior of flour. According to a particularly advantageous embodiment, it is proposed to work in a range of over 0.1 kg / cm ² , preferably over 0.4 kg / dm ^2, as the compression pressure. Best results were found in the range of 0.4 kg / cm ² -1 kg / cm ² . Higher pressures can be selected, but have the disadvantage that the product clumps in part, and at very high pressures there is a risk that the flour will be damaged. 6 kg / cm ² was also used for tests, but the piston was allowed to run to the stop.

From what has been said it is clear that the measurement on the condensed Product has to be made, as until today only within one Product stream reproducible conditions can be established without having to take the product out of the product stream.

Figs. 5 and 5a shows an entire measurement section 24 for the new invention. From a main line 20 , in which the main product stream flows, a branch line or a bypass 21 is connected, which is connected to the main line 20 again via a pipe section 22 . A transfer piece 23 represents the connection between the main line 20 and the bypass 21. The measuring section 24 has an upper press chamber 25 and a vibro outlet 26 , in which there is a vibrator 27 which, together with a housing 28 of the vibro outlet 26, has an adjustable metering gap "X" forms. Pressure means 29 and a sensor 30 are arranged in the lower third in the pressing chamber 25 . The pressure means 29 consist of a pneumatic cylinder 31 , a pneumatic piston 32 and a plunger 33 which is displaceable with respect to the press chamber 25 along the axis of the pneumatic cylinder 31 . The plunger 33 has a curved pressure surface 34 , which is directed like a blade against the sensor 30 . In the sensor 30 there is an optical system 37 and an evaluation electronics 38 , from which the digital signals are transferred via a standardized interface 39 to a microcomputer 40 or a minicomputer 35 . The microcomputer 40 can be connected directly to a printer 36 . The command unit for the entire measuring section 24 is formed by the microcomputer 40 , which controls the vibrator 27 and the pneumatic cylinder 31 via the evaluation electronics 38 and at the same time prepares and initiates the measuring phase via the sensor 30 .

FIGS. 6 and 6a show another embodiment of a measuring section. The device for compressing the material to be measured here consists of two inflatable air cushions 45 which are arranged along the measuring section and which are arranged within the measuring section 25 . The two air cushions 45 are fed via pneumatic lines 46 and a pneumatic pressure transmitter 47 and controlled via a control head 48 . The control head 48 is controlled by an electrical control cable 49 from the micro computer 40 , as is the vibrator 27 . The microcomputer 40 also controls the entire measuring game here, analogously to the solution according to FIG. 5.

Fig. 7 shows a further particularly advantageous embodiment of a measuring section. The basic structure is also the same here as in the embodiment according to FIGS. 5 and 6, except for the type of mechanical device for compressing the measured material in the area of the measuring sensor 30 . A measuring section 50 is therefore slightly modified. In all three from Figure 5 exemplary embodiments., 6 and 7, the measuring section (compression space) 25 is given by a tube-like housing. It is particularly important in the solution according to FIGS. 5 and 7 that the baling chamber is slightly expanded downwards. The cross-sectional area of the measuring section (press space) 25 increases downwards. This not only reduces the influence of the wall friction on the product, but also eliminates any interference caused by the mechanical components in the measuring section (press chamber) 25 . In Fig. 7, the device for sealing the material to be Ver consists of a spoon 52 which is designed to be pivotable about a horizontal axis 55 via a spoon holder 53 within the measuring section (pressing space) 25 . The spoon holder 53 is fixedly connected to a lever 54 via the axis 55 and can be driven by a pneumatic cylinder 56 . The pneumatic cylinder 56 is articulated for the required pivoting movement via a bolt 57 via a bearing 58 on the measuring section (press chamber) 25 . The spoon 52 can thus perform a movement (arrow 59 ) which is analogous to the movement of the curved pressure surface 34 in FIG. 5. For the measurement, the spoon 52 is moved against the measuring sensor 30 using the mechanism described and thus pre-compresses the measured material the sensor 30 . After completion of a measurement, the spoon 52 is moved away from the measuring sensor 30 via the control, the vibrator 27 is switched on and the compressed material is thus loosened again and discharged downward.

FIG. 8 shows the use of the method according to the invention in connection with a metering screw or screw conveyor 60 , as is shown schematically in FIG. 8. The sensor 30 and the device for compressing the material to be measured 29, 31, 32, 33 and 34 are shown analogously to FIG. 5. The solution with the spoon 52 according to FIG. 7 would also be applicable here . The screw conveyor 60 is controlled by means (not shown) in such a way that a measuring chamber 61 is always filled with vented product during normal operation. The sensor 30 , the device for compressing the product and a drive motor 62 for the screw conveyor 60 are controlled by the microcomputer 40 .

FIGS. 9 and 10 show a variant of FIG. 8, a screw conveyor 70, in the region of the outlet a back pressure member 71, the opening 75 against the back by driving means 74 in the desired stroke and a desired force or of the opening 75 can be moved away. A drive motor 76 and the drive means 74 or the backflow element 71 are matched to one another in such a way that a certain pressure is maintained in the measured material for the measurement. The screw conveyor 70 works against pressure. For the preparation of the measuring phase, this pressure is built up, a device 71 is actuated to further compress the measured material and the necessary measured values are recorded by a measuring sensor 73 . After completion of the measurement, the opening 75 is released again and the continuous product throughput is restarted by switching on the drive motor 75 .

Fig. 11A shows a particularly advantageous application of the new measuring method for controlling and regulating the product mixture in a mill for the production of flour, semolina or haze.

For each product type stored, the required quantity ratios are set by a further computer 102 via a continuous flow meter 100 with an attached electronic control 101 . The product mixture is fed into the mill or roller mills 107 and sieve units 104 via a common conveyor screw 103 . The flour produced is measured in a measuring section 105 with regard to its ingredients, here for example the protein content, and the values are transferred to the computer 102 via control lines 106 . If the computer 102 now detects deviations from a desired protein target value, it automatically corrects the mixture, taking into account the time delay, until the desired actual protein value matches the target value.

FIG. 11B shows the regulation of the addition of water analogously to FIG. 11A. The amount of raw material is measured kontinulierich an automatic flow regulator 110 and the amount of water required for this purpose automatically metered in accordance with a desired reference value via a Wasserdosierer 111th Raw material and water are mixed in an intensive network 112 , ground in roller mills 113 , the flour is sieved in plan sifters 114 and the ingredients, here the water content of the flour, are measured along a measuring section 115 . The value measured by the infrared measuring device 116 is passed via a control line to a computer 117 , which in turn executes the actual value / setpoint comparison and corrects deviations according to a stored program by changing the water addition via the water metering device 111 .

FIG. 12 shows another interesting application of the new method, namely to regulate a flour mixture to predetermined values for the ingredients, for example protein, ash or color. The nozzle 90 and the outlets of the classifier compartments can be guided onto one of the three mixing screws 91, 92, 93 .

A pipe switch 90 'is attached to the connecting piece 90 , which is controlled by the computer 97 on the basis of the deviation between the desired target value for the ingredients and the actually measured value. A measuring section 94, 95 and 96 is arranged at each outlet of the mixing screws 91, 92 and 93 .

Another interesting aspect of the new process is the for the first time also control of individual parameters in the roll ver grinding, e.g. B. the roller pressure by z. B. a susceptible protein ver  change automatically monitored by reducing the grinding pressure - and appropriate control commands are issued.

Another interesting idea for the device is seen in the fact that the device for compressing the measured material z. B. in the area of the pressure surface 34 ( FIG. 5) has a resilient or elastic element for keeping the compression pressure constant. Correspondingly, the spoon holder 53 could be designed as a resilient element. The pneumatic piston can be moved to the stop and a residual pressure can be maintained by the remaining spring tension. This means that a slight yielding of the compressed product can be compensated for by a slight after-running of the device for compressing the measured material.

Claims (5)

1. A method for monitoring the constituents of flour-like foods or of food regrinds, in which the material to be measured is irradiated with infrared light during successive measurement phases and the proportion of the individual components is determined from the measurement of the reflection intensity of the spectral ranges assigned to the individual components, the material being ground continuously guided over an infrared measuring section and in addition to the forced conveyance in the area of a sensor for subsequent measurements, characterized in that during each measuring phase the forced conveying of the regrind within the infrared measuring section is exposed, then the regrind for the measurements on it Irradiation surface smoothed by pressure and in the subsequent measurement, the light reflected from the compressed regrind is evaluated by a computer with regard to the reflection intensity of the spectral ranges detected, so that the W determined in this way The individual components are compared with a target value specified by a further computer, and measurement signals for controlling process parameters are derived as a function of the determined deviations. 2. The method according to claim 1, characterized in that the abge conducted measurement signals for the control of the process parameters Raw material mixture and / or flour composition and / or water addition and / or gluten addition can be used. 3. The method according to claim 1, characterized in that the abge  routed measurement signals as default values for grinding drum settings be used. 4. The method according to any one of claims 1 to 3, characterized characterized in that the measuring phases cyclically at selectable time intervals be repeated. 5. The method according to any one of claims 1 to 4, characterized ge indicates that several individual measurements during one measurement phase executed, the measurement results of a group of measurement phases are averaged and as actual values to the second computer for regulating corresponding values be specified for the product parameters.