The present invention concerns a measuring system for automatically determining a quality of a foodstuff, and comprising a housing with at least one receiving space for receiving a product holder for a fluid or viscous foodstuff, at least one product holder which is receivable or is received in the receiving space for receiving the foodstuff, a set of one or more components in or for use in the product holder, a series of several Hall sensors which are arranged along or in the receiving space and each configured to output a signal depending on a magnetic field, a control device which is operatively connected to the series of Hall sensors and configured for processing the output signals, wherein the control device is configured to detect, by means of the signals from said Hall sensors, a component of the measurement system introduced into the receiving space.

Such measuring systems are used to determine properties, and changes therein, of in particular fluid and viscous foodstuffs. For example, W02021/066046A1 discloses such a system. In particular in foodstuffs for human consumption, it is extremely important to know the properties thoroughly. Such properties may for example relate to typical product properties such as consistency, viscosity, storage properties etc. Because of the sometimes very long shelf-life of foodstuffs, it is also sometimes necessary to carry out very prolonged measurements.

A disadvantage of such systems is that it is sometimes difficult to check whether all or the correct components are indeed present in the receiving space or even in the product holder. This may for example be because the receiving space must be closed tightly if optical measurements are to be performed, or because the foodstuff itself is opaque, which is very often the case. In all cases it is undesirable to have to interrupt the often prolonged measurements because of doubts about the presence of components.

The present invention aims to find a solution to the above-mentioned disadvantage and therefore provides a measuring system according to claim 1 , in particular a measuring system for automatically determining a quality of a foodstuff, and comprising a housing with at least one receiving space for receiving a product holder for a fluid or viscous foodstuff, at least one product holder which is receivable or is received in the receiving space for receiving the foodstuff, a set of one or more components in or for use in the product holder, which are each provided with at least one permanent magnet, a series of several Hall sensors which are arranged along or in the receiving space and each configured to output a signal depending on a magnetic field, a control device which is operatively connected to the series of Hall sensors and configured for processing the output signals, and with a memory that contains an associated combination of signals for each said component of the set, wherein the control device is configured to detect, by means of the signals, in particular from the order and/or polarity of the signals from said Hall sensors, a component of the measurement system introduced into the receiving space, and to identify the component on the basis of a comparison of the detected signals with said combinations stored in the memory.

The invention is based on the concept that magnetic fields can easily be detected, are sufficiently distinctive in for example their strength and/or polarisation, have no energy costs when provided in the form of permanent magnets, and hence can be detected reliably. In addition, magnetic fields are rarely if ever disrupted by foodstuffs or their additives, even if the foodstuff is highly viscous and opaque.

In the invention, a component comprises at least one permanent magnet. This evokes a permanent magnetic field which is detected by the Hall sensors. The peak signal is dependent on a number of factors such as, for example and in particular, the distance of the magnet from the respective Hall sensor. Thus the separate Hall sensors provide different signals and hence create a pattern of signals. This pattern may be compared by the control device with patterns stored in the memory, so that it can thereby determine the correct component for the detected pattern.

In the context of the present invention, a "foodstuff" means a product that serves as a food for a non-vegetable organism. It may therefore be a foodstuff for human consumption but also for animals, or even a feeding ground for microorganisms. In fact for example milk is one example of a product which serves as a food for yoghurt cultures, wherein the resulting product is also a foodstuff for human consumption. Also the term "fluid or viscous" means that the foodstuff is a liquid which may have a low to high viscosity.

Particular embodiments of the invention are described in the dependent claims and will be discussed in more detail below.

In some embodiments, the control device is configured to determine the position of the component from said combination of signals. In such cases, it may be useful to know not only the presence but also the position of the (or each) component in the product holder or receiving space. For example, the position may change during sampling, as will be discussed in more detail below. It is then important that this other position is not assumed too early or too late. Because in these embodiments the control device is configured to monitor the position of the (or each) component, the correct position can be checked. For example, the position can be determined as the position of the Hall sensor which measures the strongest signal. It is also possible that this only measures the position of the (only or strongest) magnet in the component. Nonetheless, the relevant position can then be determined from other stored information about the detected and identified component.

Alternatively or additionally, the control device is configured to determine the orientation of the component from said combination of signals in the series of Hall sensors. It is possible to determine the orientation of a component since the orientation of a magnetic field can also be determined by a Hall sensor. This is useful in particular if a component can be placed upside down in the product holder or receiving space. Naturally, the magnet of the component concerned should then be moved such that such a reversal also causes a reversal of, or at least a change in, the polarity of one or more signals from the Hall sensors. For example, the north and south poles of the magnet are placed one above the other. Alternatively, the control device may also be configured to determine, on the basis of the detected absolute position of the magnet of the component, whether the component is correctly oriented. If the magnet is placed eccentrically, a reversal or otherwise incorrect orientation of the component will lead to a detected position of the magnet which deviates from the expected position.

In useful exemplary embodiments, the set of components comprises at least one of an additive vessel with an openable closing means, a homogenising means which is displaceable in the product holder, and a brush which is movable in the product holder.

An additive vessel may contain any material that can be added as an additive to the product space, at least to a fluid or viscous foodstuff present therein, by opening the closing means such as a lid, flap or valve under control by the control device. The aim may for example be to test how the viscosity or another property of the foodstuff changes by the addition of the additive. The additive may for example be a known quantity of a microorganism or other decay-causing organism, or a chemical substance etc. The addition of the additive may be linked to the setting first of the desired conditions in the product space such as a specific temperature or similar. In addition, the time aspect may be decisive, wherein the time determination may be less precise for manual application. For all these reasons, use of an additive vessel may give more reliable results. The presence of such a vessel may be monitored by the control device by establishing the presence of a magnet belonging to the vessel. The position of the vessel may be established by the control device by determining the position of said magnet. For details concerning the additive vessel, reference is made to application NL2031245 filed at the same time as the present application.

In particular, the closing means also comprises a (second) magnet and the control device is configured to establish whether the closing means of the vessel is (still) closed by establishing the position of the second magnet, either absolutely or relative to the position of the vessel. Also, the opening of the closing means under control by the control device may be monitored by the control device by monitoring the position of the closing means and the change therein. Advantageously, the closing means can be removed from the vessel so that opening can be clearly established. Alternatively, in some cases it is also sufficient if the closing means, such as a flap, can pivot sufficiently, or even perform a reciprocating movement. It may also be sufficient if a magnet is arranged not in the additive vessel itself but only in the closing means, wherein the control device is then configured to recognise the presence of the additive vessel with the closing means by determining the position of the magnet of the closing means. This position is however also determined by the additive vessel.

A homogenising means in the context of the present invention is an aid for mixing and homogenising the foodstuff and where applicable an additive. A known example is a magnetic agitating rod, but other examples can easily be found. Reference is made for example to the above-mentioned document WO2021/066646A1. The presence and in some cases position or similar of such a homogenising means may be crucial for the success of measurements, at least for the reliability or precision thereof. It is also favorable if the control device is configured to determine the presence, and in some cases position and/or orientation, of such a homogenising means. The type of homogenising means may also be very important. A homogenising means for a low viscosity foodstuff may have different properties from a homogenising means for a very syrupy oil or paste, in order to mix this well for example. According to the invention, it is then also favorable to be able to detect and identify the correct type from the magnet or magnets arranged therein and the signals induced thereby in the Hall sensors.

A brush which is movable in the product holder in the context of the present invention is a body which is designed for cleaning in particular the side of the product holder and/or the measuring probe in contact with the foodstuff, i.e. the inside or outside respectively. For this, the brush may be equipped with flexible or non-flexible protrusions such as hairs or lips, and be provided with a mechanism for moving the brush inside the product space in the product holder. Also for the brush, it is favorable if the control device can determine the presence, and in some cases also the position and/or orientation thereof, such as again by means of a magnet arranged on the brush and the detected pattern of signals induced thereby in the Hall sensors.

In particular, each of the components of the set comprises a group of one or more permanent magnets, wherein the groups all differ from one another in number, strength and/or orientation of the magnets. In principle, it is possible to provide each component with a same magnet, and determine the presence, and where applicable the position and orientation thereof, on the basis of the pattern of the signals induced in the Hall sensors, and where applicable the position and order of the signals. Nonetheless, it is advantageous if the respective groups of magnets differ from one another. For example, some or all components comprise two or more magnets. These magnets may be arranged in the component at different or the same distances from one another, and/or may have different or the same strengths, and/or may have different polarity, i.e. the north-south direction runs differently. All such variations lead to a different pattern in the signals in the Hall sensors. Thus each component can be identified more easily by the control device, irrespective of orientation and/or position of the component. The pattern of a unique group of magnets is itself again unique.

The pattern in the signals of Hall sensors as induced by a component may, as described above, be selected to be unique. The effect of the one or more magnets in a component on the signals of the Hall sensors is also partly dependent on the position of said one or more magnets relative to the Hall sensors. If a component should have assumed a specific fixed position in the product holder, the control device can compare the pattern measured by the Hall sensors directly with the patterns stored in the memory, and thus detect and identify the component. For example, a movable part such as a homogenising means should be at the bottom of the product holder when the magnetic coils are switched off. Conversely, an additive vessel should be situated at a well-defined location in the product holder.

If the component may be present at various positions, it is more difficult to establish clearly. However, it is then possible to allow the component to move, for example under gravity, or by moving it in the product holder with magnets, such as energised magnetic coils. The one or more magnets of the component should then cause a well-defined variation in the signals of the Hall sensors. For example, the control device may check that a specific Hall sensor has a maximum signal strength when the component passes it. Thus the control device can determine a relative position of the component, at least of the strongest magnet therein, relative to the last-mentioned Hall sensor. The control device can then make a comparison between the stored patterns and the pattern with the maximum, and determine from this which component belongs to the detected pattern of the Hall sensor signals.

In principle, inter alia the strength of the signal measured by the Hall sensors is dependent on the distance between the magnet and the Hall sensors. Advantageously, the group of magnets of one or each component comprises or is a circular magnet, or a magnet concentric with a longitudinal axis of the component. In most practical cases, both the receiving space and the product holder have a rotationally symmetrical form with a longitudinal axis, and in most cases this applies to the one or more other components. Because in such a case the distance of the component from the Hall sensors, and the magnetic field as a whole, does not change when the component is rotated around the longitudinal axis, the detection and identification is independent of such a rotation.

Alternatively, the group of magnets per component may also consist of a plurality of smaller magnets. A large number of magnets per component means a lower sensitivity to rotation. Alternatively, a group of magnets may also comprise one or a few magnets, wherein both the product holder and the other component comprise a respective abutment part, wherein said respective abutment parts hinder the rotation of the component in the product holder. For example, a groove in the product holder and a protrusion in the other component. Thus the orientation around the longitudinal axis is determined, whereby a distance change from the Hall sensors on the basis of a rotation is no longer possible, while movement up and down is still possible.

In some embodiments, the measuring system is provided with a measuring probe received in the product holder, with a sensor for determining a quality-related sensor value. The measuring probe of the measuring system comprises a sensor for determining a quality-related sensor value. Such a probe may be of many types, such as a sensor for an electrical variable such as conductivity or dielectric properties, a thermometer, a turbidity meter, a camera for optical measurements etc. The measuring probe may also comprise multiple sensors such as in particular a thermometer and a supplementary sensor.

By means of automatically detecting and identifying components, the control commands can control the measuring system. Thus, in some embodiments, the control device is configured for outputting a status signal and/or a control command depending on the detection and identification of a predefined subgroup of said set of components. For example, the control device may indicate that a specific component, which e.g. has been previously defined as necessary for an experiment, is not present or at least not detected. Also, the control device can refuse to perform a measuring program if not all required components are detected. Of course it is possible and should be preferred if the control device gives this status information during preparation of the measuring system, so that no later refusal need occur. It is however possible that a component will fail, or otherwise no longer be recognised. It is also favorable for the reliability of the measuring system and its perceptions if the control device then outputs an associated status signal and/or outputs or no longer outputs a predetermined control command.

According to these embodiments, it is also possible to gain information on the interior of the housing without having to open the measuring system. If for example a new experiment is to be started, an operator need merely indicate in the control device which components are required. By detection of these components (previously or on the basis of the indication), the controller may indicate whether the experiment can be performed without needing to open the product holder.

In very favorable embodiments, the measuring system furthermore comprises a series of magnetic coils which are arranged along the receiving space and each of which can be energised independently and separately by the control device. By means of such magnetic coils, one or more components can be moved up and/or down, preferably even independently of one another. For details of this, reference is again made to document WO2021/066646 A 1 . An important advantage of these embodiments is that the magnets, which are necessary to be able to move the component concerned with the magnetic coils, can also ensure detection and identification of the component by means of the Hall sensors. Another important factor here is that the Hall sensors can themselves serve as sensors, for example when measuring the viscosity of the foodstuff. Again, for details reference is made to WO2021/066646A1.

Thus various components may fulfil a double function, which is favorable for limiting the complexity of the measuring system and improving the functionality and reliability of the measuring system.

Another important remark is that the series of Hall sensors may also be used instead of the measuring probe with the sensor which may be arranged in the product space, in particular for determining a viscosity value of the foodstuff in the product space, by means of a magnetic component movable in the product space and on the basis of the measurement signals determined by the Hall sensors during movement of said magnetic component. The invention then concerns a measuring system for automatically determining a quality of a foodstuff, and comprising a housing with at least one receiving space for receiving a product holder for a foodstuff in a receiving direction, a set of components for use in the measuring system, which are each provided with at least one permanent magnet, and comprising at least one product holder for receiving the foodstuff, a series of several Hall sensors which are arranged along or in the receiving space and are each configured to output a signal depending on a magnetic field to the control device, a control device which is connected to the series of Hall sensors with a memory that contains an associated combination of signals for each said component of the set, wherein the control device is configured to detect, by means of the signals, in particular from the order and/or polarity of the signals from said Hall sensors, a component of the measurement system introduced into the receiving space, and to identify the component on the basis of a comparison of the detected signals with said combinations stored in the memory, wherein the control device is furthermore configured to determine a viscosity value of the foodstuff in the product space by means of a component magnetically movable in the product space and on the basis of measurement signals determined by the Hall sensors during movement of said magnetic component.

The invention will now be explained in more detail with reference to some non-restrictive exemplary embodiments and the drawing. In the drawing:

Figures 1A, 1 B and 1C show in schematic cross-section a measuring system according to the invention in three stages during use;

Figures 2A, 2B and 2C show schematically exemplary signals of the Hall sensors according to the situations of the respective Figures 1A, 1 B and 1C; and

Figures 3A, 3B and 3C show schematically a product holder with only one measuring sensor, with a mixer in the correct position, and with additionally a mixer in an upside-down position, respectively, as well as the signals of the Hall sensors shown.

Figures 1A, 1 B and 1C show a measuring system 1 according to the invention in three stages during use, in schematic cross-section.

Figure 1A shows a measuring system with a housing 2, a receiving space 3 and a lid 4. A product holder 5 has a product space 6 with a foodstuff 7 therein. Reference 8 indicates a probe with four electrodes 9 which are connected, as is a camera 10, to a control device 11.

References 12-1 , 12-2,... 12-n indicate magnetic coils, and 13-1 to 13-n indicate Hall sensors. An additive vessel 14 with a first magnet 15 contains an additive 16 and is closed by a lid 17 having a second magnet 18. A mixer 19 has a third magnet 20.

The measuring system 1 shown here has a housing 2 with a receiving space

3 for only a single product holder 5. It is quite possible to provide a larger housing and receiving space for multiple product holders. Since such a larger number makes no substantial difference to the invention, no further attention will be here paid to such larger number.

The product holder 5 is usually made of glass, for example for better perception of the contents such as with the camera 10, and because of favorable properties of many glass types, such as chemical resistance. Nonetheless, other materials such as stainless steel or similar are not excluded. The product holder 5 is here largely filled with a foodstuff 7. The foodstuff is a fluid or viscous foodstuff such as a dairy product, fruit juice etc., but may also be water.

The additive vessel 14 contains an additive 16, such as a powder which must be dissolved in the foodstuff 7, or a substance which must provoke or simulate a reaction such as ripening or perishing, such as a bacteria or mold culture etc. Examples are instant dessert powders, soluble coffee or tea, milk powder etc. For such additives, the dissolution behavior is of course important: how quickly and how well it dissolves, whether lumps are formed, the temperature dependence etc.

Measurements on the foodstuff 7 - with or without the additive 16 - can be carried out e.g. by a sensor, such as the optional electrodes 9 on the also optional measuring probe 8. These electrodes may for example measure in pairs the real and imaginary parts of the impedance of the foodstuff, which in itself is a known technique. Also, the optional camera 10 may perform optical measurements, such as with respect to turbidity and/or color of the foodstuff. If required, a light source may be provided (not shown here). Other sensors are also possible. One important example is a Hall sensor device comprising several Hall sensors, here indicated with reference signs 13-1 to 13-n, wherein the larger the number n between 8 and 20, the finer the resolution of the detection or monitoring. The Hall sensors 13 detect a magnetic field and also when this moves. If a component of the measuring system 1 is provided with a magnet, then the Hall sensors 13 can detect this, and also whether the position, and where applicable a change therein, of a component is as desired. This information can be used in at least two ways, for example by the mixer 19, as will be explained below.

On dissolving of the additive, it is often important that it is mixed with the foodstuff 7 according to fixed protocols by means of a homogenising means, in this case the mixer 19. For example, immediately after adding the additive, move up and down ten times, and then every hour ten times back and forth, or whatever is desired. The mixer comprises a (third) magnet 20 with which it can be moved up and down by means of the magnetic coils 12-1 to 12-n which can be individually controlled by the control device 11. This makes it possible to carry out the mixing in a highly controllable fashion. Checking the mixing itself however is often not easy to carry out, for example the housing 2 and/or the product holder 5 are made of an opaque material, but often because the foodstuff 7 or the mixture of the foodstuff 7 and additive 16 is turbid or opaque.

In order yet to be able to monitor the mixing and make measurements more reliable, the invention provides for monitoring the position of the mixer 19 by means of the third magnet 20 and the series of Hall sensors 13-1 to 13-n. As described above, by means of the Hall sensors operatively connected thereto, the control device can determine the position of the third magnet 20 and hence of the mixer 19. By repeated detection, also any movement of the mixer can be detected. Thus the control device 11 can monitor whether the planned mixing with the mixer 19 also actually takes place.

In addition, with the help of the mixer 19, the separately energisable magnetic coils 12 and the Hall sensors 13, the control device 11 can also determine viscosity values of the foodstuff. For this, use may be made of the technique described in the above-mentioned document WO2021/066646, to which express reference is made. It is important to note that with the present invention, a functionality is added without increasing the mechanical complexity.

The present invention is not only useful for monitoring the mixing. It is also useful for monitoring or checking the presence and/or position of other components. Thereto, the component concerned is provided with a permanent magnet, the magnetic field of which is detected by the Hall sensors 13-1 to 13-n. In Figure 1A, as well as the above-mentioned mixer 19 with its third magnet 20, these are the additive vessel 14 with its first magnet 15, and the lid 17 with its second magnet 18. The three magnets 15, 18 and 20 in this example each having a annular shape and a different strength, here indicated by the number of plus and minus signs, the north and south pole, respectively. Thus these three components can already be uniquely identified purely on the basis of the detected signal strength in the Hall sensors 13, and their respective positions determined. This will also be explained in more detail with reference to Figures 1A-C and 2A-C, but it is clear that the position of the lid 17 is at the site of the weakest peak signal unequal to zero, that of the additive vessel 14 at the site of the next weakest peak signal, and the mixer 19 at the site of the strongest peak signal. If two components are so close together that the signals evoked by the respective magnets overlap, the control device can still detect their presence, for example if the combined signals lead to a unique strength. When choosing the strength of the magnets, advantageously this can be taken into account, for example by choosing the mutual strength ratio as a prime number. Also, the components such as the mixer 19 may be provided with two or more magnets (as rings or not) or groups of magnets (as rings or not) at a mutual distance. Such sets of magnets per component also lead to clearly identifiable patterns in the signals in the Hall sensors 13 which are processed by the control device 13 into a recognised component. For example, it may be important to confirm that the correct mixer 19 is in the product holder 5, selected for example depending on the viscosity of the foodstuff 7.

For monitoring the release of additives 16 from the additive vessel 14, the control device 11 may for example monitor the position of the lid 17. For this, reference is made to Figures 1A-C. It is pointed out that for the sake of clarity, the components not necessary for this explanation are not repeated in Figures B and C. In Figure 1A, the mixer 19 is at the bottom and the lid 17 closes off the additive vessel 14. This closure may for example be achieved by the second magnet 18 being attracted sufficiently strongly by the first magnet 15, because a (weak) mechanical connection exists between lid and vessel, etc.

For the purpose of opening the additive vessel 14, the mixer 19 is moved upward by targeted activation of magnetic coils 12-1 to 12-n. In Figure 1 B, the mixer 19 is moved up and now lies against the lid 17. The stronger third magnet 20 now lies much closer to the second magnet 18 than the first magnet 15, which is also weaker. If the magnetic coils 12-1 to 12-n are again energised in targeted fashion to move the mixer 19 down, the mixer will carry the lid 17 with it and thus open the additive vessel 14 so that additive 16 is released and can mix with the foodstuff 7. This situation shown in Figure 1C.

Figures 2A, 2B and 2C show schematic exemplary signals of the Hall sensors which would be found in the situations in Figures 1A, I B and 1C respectively. The starting point is ten Hall sensors 13-1 to 13-10 (only shown in Figure 2A), and hence ten signals. Again, the parts not relevant to this explanation have been omitted.

The signals from the Hall sensors are shown schematically here, in arbitrary strength normalised to 1. The situations shown are momentary measurements. In practice, the Hall sensors may perform repeated measurements, even during movement of components in the measurement system.

Figure 2A shows at the bottom, at sensors 13-8, 13-9 and 13-10, a strong signal with a polarity which points to "north" or "plus" at the top, and "south" or "minus" at the bottom. This indicates the mixer 19, as the control device 11 can determine by comparing the signals, their strength and polarity, with those stored in a memory of the control device (not shown separately). Sensors 13-5, 13-6 and 13-7 give almost no signal, indicating that no component with a magnet is present there. Sensors 13-3 and 13-4 give a relatively weak signal with the same polarity as for the mixer 19. This signal indicates the lid 17. It can be seen from the position that the lid is closed. Finally, sensors 13-1 and 13-2 give a relatively strong signal which indicates the presence of the additive vessel 14.

Figure 2B shows that the sensors 13-1 and 13-2 give an almost unchanged signal. After all, the position of the additive vessel 14 has not changed. However below this, sensors 13-3, 13-4 and 13-5 now give a changed signal showing a wider and relatively strong peak. This indicates a mutually close combination of the mixer 19 and lid 17. Below this, for sensors 13-6 to 13-10, no significant signal is perceptible, which corresponds to the absence of a component with magnet.

In Figure 2C, the signal of the additive vessel is still visible at sensors 13-1 and 13-2. Now at the bottom, for sensors 13-9 and 13-10, there is a changed but quite strong signal which now indicates the displaced combination of the mixer 19 with lid 17. Note that the combination of mixer 19 and lid 17 at the bottom, i.e. sensors 13-9 and 13- 10, does not need to assume a relative position comparable to that of sensors 13-3, 13-4 and 13-5. For example, the combined center of gravity may lie first at the height of sensor 13-4, and at the bottom between sensors 13-9 and 13-10. So the absolute signal form may differ. Nonetheless, the signal in Figure 2B at sensors 13-3, 13-4 and 13-5 as measured during the fall should also be measured at the combination of sensors 13-4, 13-5, 13-6, the combination 13-5, 13-6 and 13-7, etc. Thus it can still always be guaranteed that the measurement signals belong to the combination of mixer 19 and lid 17.

Figure 3A, 3 B and 3C show schematically a product holder 5 with only one measurement probe 8, a product holder 5 also with a mixer 19 in the correct position, and a product holder 5 also with a mixer 19 in an upside-down position. Each part figure also shows the signals of the Hall sensors 13-1 to 13-10 shown.

In Figure 3A, no component is present with a magnet. Hence the sensors 13 give no perceptible signal. In Figure 3B, the mixer 19 is arranged similarly to Figure 2A. The associated signals in sensors 13-8, 13-9 and 13-10 then also correspond. In Figure 3C, the mixer 19 is arranged upside down so that the "north pole" and "south pole" of the magnet 20 are also upside down. As a result, the signals from sensors 13-8, 13-9 and 13-10 may indeed have the correct size but with reversed polarity. The control device will recognise such a reversed polarity and conclude that the mixer 19 is present at the position of sensors 13-8, 13-9 and 13-10 but arranged wrongly. This is naturally important to be able to carry the lid 17 with it. The invention thus provides a way to monitor the correct positioning even if the component concerned (here the mixer 19) is not visible from outside the product holder 5 or even the measurement system.