WO1989010548A1

WO1989010548A1 - Device and process for on-line measurement of product parameters

Info

Publication number: WO1989010548A1
Application number: PCT/CH1989/000076
Authority: WO
Inventors: Bernd Kuehnemund
Original assignee: Gebrueder Buehler Ag
Priority date: 1988-04-29
Filing date: 1989-04-28
Publication date: 1989-11-02
Also published as: EP0371099A1; JPH03500208A

Abstract

Novel device and process for on-line measurement of two or more product parameters of a continuous product flow conveyed through a conveying duct (1, 2, 3), whereby one section (2) of the product conveying duct is designed as a container (4) supported on weighing elements (5) and having a bottom seal (6). Included in said container (4) is a sampling device (10), which can be selectably opened either in the direction of the product flow or in the sample-taking direction. In particular, the flow of conveyed material is blocked, whereby the material throughput at a given moment as well as at least one other parameter, such as for example the humidity of the product or the protein content of a grain mixture, are determined.

Description

Device and method for the online recording of product parameters

The invention relates to a device and a method for the on-line detection of two or more product parameters of a continuous product stream flowing in a delivery line.

Industrial processing of food and feed is currently under strong pressure to increase the degree of automation in the production process.

The current status is characterized by three circumstances.

First, more and more rapid and precise laboratory analysis devices are available for the continuous monitoring of the product parameters. The internal structure of these devices is so complex that even highly trained food chemists can no longer understand them. On the other hand, the handling of the devices has been simplified to a degree that even personnel can operate them reliably without special training.

Secondly, the recent progress in the construction of measuring devices, especially because of the robustness of the whole apparatus, has allowed it to be used in the harsh conditions of the manufacturing process.

The third point sums up, as it were, the main weaknesses of the entire known development to date. The specialist training of everyone, that is to say both the food chemist, the laboratory technician and the miller, has always placed great emphasis on the problem of taking small samples of material which are representative of the amount of product to be assessed. The classic training mostly concentrates strongly on taking product samples from a quantity of product resting in vessels, in containers, silos etc., but much less on a flowing product stream.

Many product parameters, especially in the case of foodstuffs, are monitored by human sensor technology, and in case of doubt the sampling is repeated until the desired result is obtained, directly in the production process itself. The new invention assumes that this part will remain, at least least should not be ousted. On the other hand, it has been the more unsatisfactory for a long time that a large part of the parameters that have been monitored by apparatus for a long time take place separately and spatially from production in an extra laboratory. This greatly affects the increase in the degree of automation. In many cases it is not possible to implement real regulations, ie to measure on site and correct immediately in production.

One aim of the invention is precisely to capture the product parameters, which are currently still being measured in the laboratory, on-line in the production itself, the main object of the invention being to have at least two product parameters either simultaneously or to measure at least from the same product sample without significantly disturbing the product flow. The apparatus laboratory technology should therefore be relocated to the production plant itself in order to achieve a real increase in automation while at the same time increasing (better and faster) the assurance of the qualitative properties of the material to be processed.

The solution according to the invention is characterized in that a section of the product delivery line is designed as a vessel, supported on weighing elements and having a bottom closure, in which a sampler is integrated, the sampler being optionally openable, in the direction of the product flow or in the direction the sampling.

It was only the new invention that made it possible to realize that, with all previous searches for real problem solutions, these have always, without exception, always been based on a single, very specific task, so that a correspondingly large number of special apparatuses had to be developed. The new invention assumes, however, that not only do many factors interact, but that they also help each other to improve the measurement result in a supportive sense. For the weighing of bulk goods, the bulk goods are stowed in a weighing container. If you take a sample from the traffic jam, you get the least possible segregation. It is known that very large deviations in the pattern composition arise when a product sample is collected at some point from a product stream falling loose in a tube without any special precautions. Furthermore, it has also been recognized that there are basically a few critical points in the production process where the product quality is recorded, the throughput usually also being recorded at the same point in order to increase the degree of automation. An automatic mill operation requires a very high level of accuracy for the monitoring of the product throughputs, since a deviation of +/- 1%, for example with a daily throughput of 500 t, would already mean a difference of +/- 5 t (Balance accuracy).

For many measurement methods, e.g. the capacitive recording of the product moisture, the bulk material not only has to be brought to a uniform bulk density, but this must also be measured. Systems similar to scales are also used for this. For a protein measurement with infrared, a reproducible bulk density even has to be produced, this also with mechanical additional devices, in order to obtain a sufficient reproducibility of the measurement results.

In contrast, the new invention allows the simplest means, essentially with one device, to create the necessary basic conditions: formation of jam, uniform density, uniformity of sampling from the jammed product stream, etc. The second or. Any further measured value can be recorded - with the heart of a scale with an integrated sampler. For many cases, all measurements can be solutions even in a horizontal plane, compared to the known solutions, where for each additional measurement a further product extraction height section distributed over the height required. In practice, there is often not enough free height, for example in the case of a product downpipe, so that, particularly when the measuring devices are installed later, they often have to be installed at very problematic points with regard to taking product samples.

Yet another advantage of the new invention is added. Each further product parameter that is still being measured is taken from the same product sample that was also weighed. However, an additional basic sampling rule is thereby fulfilled free of charge: Take a representative sample of this and so many kg of the product and draw the laboratory sample from it. Another, not negligible, advantage is that each further product parameter is clearly related to the throughput currently given. So, for example: The grain has 13.5% moisture and 14% protein content and the associated current throughput was 42t / h with a product temperature of 35 ° C. Such information also allows real conclusions to be drawn, be it on the current quality of the products or the necessary corrections to the processing machines.

As will be shown in the following, the invention allows a number of additional, very particularly advantageous configurations.

The sampler is thus preferably arranged laterally, at least over a substantial part of the height dimension of the vessel. This will remove the sample from the entire layer area over the sample height formed, which arises during filling. The sample itself is thus already a mixture over the corresponding time of filling the vessel.

The simplest solution is when the sampler is formed from a half-shell, which can be brought into the open or closed position either with respect to the product stream. In the open position, the product flow flows through the sampler and thus gives a self-cleaning function.

In the case of a further design idea, a measuring device can be assigned directly to the sampler, wherein the measuring device can be firmly connected to the vessel, that is to say it can be weighed in each case or can be separated in terms of weighing technology. Particularly in those cases in which a small sample has to be produced from the sample itself, the sampler is preferably connected via a closable opening to a sample discharge line or to a sample receiving device which is separated in terms of weighing technology, with the sample receiving device being connected to an additional sample may have participants.

If a particularly high degree of uniformity of the sample is required with regard to the representation of the sample for the product stream, the sampler is arranged in an inclined side wall of the vessel. In this way, not only do different product parts of the layer parts stored above the vessel height collect, but different cross-sectional zones are also involved in the sample formation from the inside out. Furthermore, it is possible to assign a mechanical forced micro-sampling device to the sampler, which can consist of a screw conveyor and, if necessary, can be supported on the weighing vessel.

With regard to products such as flour, which are flowable but not free-flowing, the sampler preferably points both in the closed direction in the direction of the product flow and in the opened one

Position in relation to the product flow only those surface elements which are vertical or are so steep that they do not hinder the product flow in the vessel and are self-cleaning while the product flows out of the vessel.

It is particularly expedient if the sampler can be rotated, the sample being able to be brought into a position separate from the product flow and after measurement back into the product flow and after measurement back into the product flow.

The new invention further relates to a method for the on-line detection of two or more product parameters of a continuous bulk material flow, which is characterized in that, in order to determine the throughput, the product flow is stowed in a continuous weighing vessel in a manner known per se, and during or immediately after measuring the throughput from the accumulation (from the solid) in the weighing vessel, a product sample is mechanically taken and can be separated from the product stream in order to record a second or further product parameter.

It is envisaged that the weighing on traditional after filling the vessel, stopping the inlet and weighing the contents after a brief calming. In this case, the product sample would be separated immediately before the contents of the vessel were drained.

In a second case, the throughput can also be recorded during the filling through the weighing elements and the product sample would be separated after a sufficient filling level in the weighing vessel has been reached. In this case, the weighing process is fundamentally not disturbed, since the separated product sample also remains part of the weighed container content.

However, it is also possible for the product feed into the weighing vessel to be stopped briefly and for the density of the bulk material to be recorded by draining the sample alone and the remaining weighing vessel content at a separate time, since the volume of the sample chamber is constant and thus predetermined.

The new method allows a very large number of measurement methods. Thus, the moisture and / or the protein content and / or the brightness and / or the ash content and / or the granulation etc. can be measured from the sample.

The new invention will now be explained in more detail with the aid of some exemplary embodiments, wherein:

1 is a schematic representation in cross section. FIG. 2 shows the sample divider on a larger scale,

3a, 3b, 3c each show a section III-III from FIG. 1 in three rotational positions of the half-shell of the sampler,

4a, 4b, 4c, show three different measuring positions, each with varying sample treatments,

5a, 5b show two steps for the measurement value acquisition, FIGS. 6a, 6b, 6c show the application of the new invention with the so-called negative weighing.

In the following, reference is now made to FIGS. 1, 2 and 3. The device consists of a feed pipe 1, a weighing part 2 and a discharge pipe 3. The weighing part 2 is designed as a real balance, a weighing vessel 4 being supported on electronic weight sensors 5 and having a bottom closure flap 6. The weighing vessel 4 is arranged via flexible sleeves 7, separated from the stationary parts of the system, by weighing technology.

All functions of the device are controlled by an appropriately programmable computer 8. The actual essence of the new idea is that the weighing part 2 simultaneously has the function of sampling or a device 10 for sample measurement. This device 10 can be a complete unit with the weighing be part »The central idea is that not only can the sample simply be weighed, as is common practice in some cases, but that the scale is intended as part of the main product line for the main product flow, so that it is truly online with scale accuracy the throughput can be determined, and with the same device further parameters, for example the bulk density, the moisture, the protein content, ash content, the grain analysis, etc. can be determined from the product stream by forming a representative measurement sample are. The jam of the falling product stream required for the actual weighing is used for the sample preparation. In some cases, in order to switch off any batch of product separation in the weighing vessel, it may be necessary to provide so-called diffuser plates 11 known per se over the entry region of the weighing vessel 4. It may also be advantageous to provide an inlet slide 9 at least for verifications of the balance.

The device 10 for sampling is shown again on a larger scale in FIG. The exemplary embodiment shown here has a recess 12 on the side of the weighing vessel 4, see FIGS. 3a, 3b, 3c, an enlarged space 13 (horizontally hatched horizontally) being formed on the outside by a corresponding semicircular extension 14. A half-shell 15, which is rotatable about a vertical axis, lies in the same shape as the travel extension in the space 13. FIG. 3a shows the half-shell in an open position after the weighing vessel 4. The weighing vessel 4 is thus expanded by the "horizontal-vertical" hatched space 13. In the position in FIG. 3a, the space 13 also fills with the material to be measured. If the space 13 is filled with material to be measured, a measurement sample can be made by rotating the half-shell 15 are cut out as it were (Fig. 3b). After the half-shell 15 has been rotated through 180 ° (FIG. 3c), the measurement sample, which was previously part of the goods lying in the weighing vessel 4, is now separated (vertically and obliquely hatched) in a measurement sample room. For a reliable function, the rehearsal space can be formed, as can be seen in FIG. 2, a counter-half shell 17 which extends after the interior of the weighing vessel and which forms a fixed wall part of the weighing vessel 4. The half-shell 15 here only has one conical end 18 and one each at the top and bottom. 19, but these are, as shown in FIGS. 3a, 3b and 3c, individually and independently rotatable about a vertical axis 20. The rehearsal space 16 can be opened or closed, and all movement functions can be coordinated or controlled by the common computer 8 via corresponding motor means. In the case of particularly delicate products which tend to segregate very strongly, the part of the vessel wall on which the sampling device is attached can be inclined. If the weighing vessel 4 is tapered downwards at the same time, the inclined sampling also removes product for the sample over a large area across the cross-section. The axis 20 is then also inclined.

Figures 4a to 4c now show the operation of the new invention in three possible basic positions. In Figure 4a, the entire device is flowed through without measurement and cleaned at the same time. The weighing device can, of course, be designed, for example, according to international application No. WO 85/01577 or international application No. WO 86/05875, both of the texts mentioned being an integral part of this application. In the case of execution according to international application no. WO 86/05875, as shown, maintains a constant flow in the weighing vessel, but with congestion in the weighing vessel 4. Here, the sample can be taken from the moving, sinking product stream, as can be seen in the second basic setting, FIG. 4b. For this purpose, a specially designed outlet flap 30 is brought into the correct position via the weighing signal. If one wants to generate a rising fill level, the outflow must be made smaller at the bottom than the inflow at the top. If you want to generate a sinking level, you do the opposite. As a result, a sample can be produced simultaneously with the generation of the weighing signal for the measurement of further product parameters. A measuring device 31, for example for determining the moisture or protein, for example by means of infrared, capacitive measuring device or microwaves, can be assigned directly to the wall part of the weighing vessels or even attached to it and weighed. However, it is also possible, in addition or as an alternative, to arrange a measuring apparatus 32 on the balance. For example, this is particularly the case if a grain analysis is to be created online or for measuring devices that can only process small samples. For this purpose, it is advantageous if the sample discharge channel 22 opens into a separate, that is to say not weighed, small sample divider 33 (FIG. 4b). In this way, a sample which is 1% or 1% or even smaller with respect to the main product flow can be produced from the small sample divider 33. The small sample divider 33 can be constructed in a known manner and a screw 38 can be formed in the form of a sample removal. This solution is particularly suitable for flowable but not free-flowing products such as flour. The embodiment according to FIG. 4a is rather intended for whole grain grains or gritty products. After the measurement, the sample can neither be returned to the main stream via a return duct 34 or 35.

FIG. 4c shows a position of the device in which a sample is separated for the measurement of further parameters, the separation being maintained until the measurement is completed. The main product stream can flow undisturbed through the entire device. Arrow 36 indicates that the

10 measuring device 31 also for example only for the

Measurement process can be moved to the rehearsal room 16. Any sample quantity can also be completely removed for other purposes via a sample distributor 37, e.g. for quality monitoring and storage of

15 production samples, for example for a possible later check.

FIG. 5a again shows a “captured” sample, and FIG. 5b shows the direct return of the sample to the main product stream.

A further, interesting application idea of the new invention is shown in FIGS. 6a to 6c. It is the so-called negative weighing. When filled

25. Weighing vessel (FIG. 6a), the input slide 9 is closed. The scale is no longer disturbed by the incoming product stream. The outlet slide 6 is also closed. In this state, the total of the good quantity (tare + good) is weighed (Fig. 6a). Then

30 (Fig. 6b) the measurement sample is drained, for which the

Slider 21 is opened. Then the remaining weight is weighed, ie weighing vessel + content, without measurement sample. Then the bottom outlet 6 is opened, all the product is drained and the empty weighing parts

35 weighed (tare). That makes it possible Determine sample weight = 6a - 6b,

and calculate the bulk density of the sample from the sample weight, which is important for many exact measurement values, e.g. for capacitive or microwave measurements.

Claims

1. Device for on-line detection of two or more product parameters of a continuous product stream flowing in a conveyor line, characterized in that a section of the product delivery line is designed as a vessel supported on weighing elements and having a bottom closure, in in which a sampler is integrated, the sampler optionally being evident, in the direction of the product stream flowing out or against the direction of the product stream for sampling.

2. Device according to claim 1, so that the sampler is arranged laterally, at least over a substantial part of the height dimension of the vessel.

3. Device according to patent claims 1 or 2, so that the sampler is formed from two half-shells, which can be brought to the product stream either in the open or closed position.

4. Device according to one of the claims 1 to 3, characterized in that a measuring device is directly assigned to the sampler.

5. Device according to patent claims 1 to 4, so that the sampler is connected via a closable opening to a separate sample discharge line or to a sample receiving device which is separated in terms of weighing technology.

6. Device according to claim 5, so that the sample receiving device has an additional sample divider.

7. Device according to one of claims 1 to 6, so that the vessel has an inclined side wall in which the sampler is arranged.

8. Device according to one of the claims 1 to 1, so that the mechanical, small-scale sampling device is assigned to the sampler.

9. The device according to claim 8, so that the forced small-scale sampling device is a screw conveyor.

10. Device according to claim 8 or 9, so that the compulsory micro-sampling device is supported on the weighing vessel.

11. The device according to one of the claims 1 to 10, characterized in that the sampler is closed both in the direction of the product flow and in the open position. Compared to the product stream, the surface element only has surface elements that are vertical or are so steep that they do not hinder the product stream in the vessel and are self-cleaning while the product is flowing out of the vessel.

12. Device according to one of claims 1 to 11, so that the sampler is rotatable, the sample being able to be brought into a position separate from the product stream and after measurement back into the product stream.

13. Device according to one of the claims 1 to 12, d a d u r c h g e k e n n z e i c h n e t that the rehearsal room itself as a measuring room, for example. for the

Measurement of the product moisture or the protein content of the good is formed.

14. Device according to one of the claims 1 to 13, d a d u r c h g e k e n e z e i c h n e t that the vessel with the weighing elements is designed as a continuous and / or as a positive and / or as a negative balance.

15. A method for the on-line detection of two or more product parameters of a continuous bulk material flow according to one of the claims 1 to 14, characterized in that for the detection of the throughput, the product flow is stored in a manner known per se in a continuous weighing vessel , and that during or immediately after the throughput has been measured from the accumulation (from the solid) in the weighing vessel, a product sample is mechanically removed and can be separated from the product stream to record a second or further product parameter.

16. The method according to claim 15, so that the product feed into the weighing vessel is stopped for a short time and the density of the bulk material is recorded by draining the sample alone and the remaining weighing vessel content at different times.

17. The method according to one of the claims 15 or 16, so that the moisture and / or the protein content and / or the brightness and / or the ash content and / or the granulation is measured from the sample.

18. The method according to claim 16, so that the content of the weighing vessel is read off and the weight of the sample is measured separately.