Device and method for analysing milk with a calibration unit

Abstract

The invention relates to a device and to a method for analysing milk with a calibration unit, wherein the device comprises a line section (2) for the milk, a light source unit (5) which emits light into the line section (2), a detection unit (6) for the detection of light, in particular the spectrally resolved detection of light, which emerges from the line section (2), and a calibration unit having a calibration element (9) which has a calibration surface (10). The detector unit (6) and the calibration element (9) can be moved relative to each other such that the calibration surface (10) of the calibration element (9) can be brought in front of the detector unit.

Description

[0001] Device and method for analyzing milk with a calibration unit

[0002] The invention relates to a device and a method for analyzing milk.

[0003] Raw milk is an important raw material, especially for the food industry. To protect consumers, ensure technical processing capabilities, and regulate the market, raw milk must meet certain national and international quality standards.

[0004] Advanced functions play a crucial role in the automatic and automated milking of dairy animals using semi- and fully automatic milking systems. Ensuring milk quality standards, particularly testing for altered milk, is paramount. Immediately or immediately after milking, the milk can be spectroscopically analyzed for its constituents. This analysis utilizes the characteristic absorption spectrum of the constituents. When light of a specific wavelength is introduced into the milk, it is absorbed if the milk contains a constituent that absorbs that wavelength.

[0005] A device for analyzing milk is known from publication WO 2022 / 189227 A1. The device comprises a conduit section for the milk, a light source unit which emits light into the conduit section, a detection unit for spectrally resolved detection of milk exiting the conduit section, and an evaluation unit which is configured to analyze the milk for its constituents based on signals from the detector unit.

[0006] WO 2022 / 189227 A1 states that the detector unit can be automatically adjusted and / or calibrated by feedback from reference values.

[0007] Considering that the quite reliable working through the

[0008] Since a device known from WO 2022 / 189227 A1 is also integrated, in particular, into automatic and automated milking systems, the present invention aims to automate the calibration of the device for milk analysis. This objective is achieved with the device and the method according to the independent claims. Further advantageous embodiments of the device and the method are specified in the dependent claims.

[0009] According to the invention, a device for analyzing milk is proposed in which automated calibration can be performed. The device comprises: a conduit section for the milk, a light source unit which emits light into the conduit section, a detection unit for detecting light, in particular the spectrally resolved detection of milk exiting the conduit section, a calibration unit with a calibration element having a calibration surface, wherein the detector unit and the calibration element are movable relative to each other so that the calibration surface of the calibration element can be brought in front of the detector unit, and in particular a first evaluation unit which is configured to analyze deviations between the signals of the detector unit and reference values, and a second evaluation unit which is configured to analyze the milk for constituents based on signals from the detection unit.

[0010] The device is suitable and intended for performing an analysis of milk obtained directly or indirectly after a milking process.

[0011] In this context, analysis refers to the examination of milk's composition. This can include testing for components such as fat, protein, and lactose, or for contaminants like antibiotics, dipping agents, cleaning agents, or water. It can also determine whether the milk contains solid particles, flakes, foam, or bubbles. The analysis may consist of distinguishing between the presence and absence of certain substances without quantifying them. This allows for determining whether the milk is contaminated; alternatively or additionally, it can, for example, determine the milk's fat content. To ensure the quality of the analysis, the device is checked to ensure that no deviation is detectable between the signals from the detection unit and reference values.For this purpose, the device comprises a calibration unit with a calibration element that has a calibration surface. The detector unit and the calibration element are movable relative to each other, so that the calibration surface of the calibration element can be positioned in front of the detector unit. This means that the calibration element with the calibration surface is positioned such that the calibration surface is within the detection range of the detector unit. The calibration surface is preferably moved into an area where there is essentially maximum light intensity.

[0012] The detector unit and the calibration element are movable relative to each other. This means that the detector unit can be stationary and the calibration element movable. It is also possible for the detector unit to be movable and the calibration element to be stationary. A combination of a movable detector unit and a movable calibration element is also possible.

[0013] Depending on whether the milk analysis is based on light reflection or absorption, the calibration element can be positioned accordingly. For example, to determine and analyze the deviation between the detector unit's signals and reference values, the calibration surface and detector unit can be arranged so that the calibration surface replaces the milk sample. In this configuration, the calibration surface is located between the detector unit and the milk sample, allowing the light from the light source to fall directly onto the calibration surface. In another configuration, the calibration surface is located in the area between the detector unit and the milk sample.

[0014] A preferred embodiment of the device is one in which the detector unit is stationary and the calibration element is pivotable, particularly rotatable. If a possible deviation between the signals of the detector unit and the reference values ​​is to be determined, the calibration element can be pivoted or rotated into the beam path with its calibration surface. It is preferable for the calibration element to be rotatable or pivotable about an axis. The pivoting or rotation of the calibration element is preferably achieved by an electric drive. Depending on the spatial constraints and the design complexity, it can also be advantageous for the detector unit to be stationary and the calibration element to be movable. If the calibration element has a suitable engagement area, it is possible for an operator to move it.To improve and increase the degree of automation, the calibration element can be moved into the detection range for the detector unit by means of, for example, traction devices.

[0015] To improve the analysis of deviations between the detector unit signals and the reference values, it is proposed that the calibration element have several different calibration surfaces. This opens up the possibility of verifying not only the functionality of the detector unit, but also the functionality of the light source unit.

[0016] As an alternative to this approach, it is proposed that the calibration unit has several calibration elements, each with a calibration surface, the calibration surfaces being distinguished by their color.

[0017] The calibration surfaces can preferably be selectively positioned in front of the detector unit.

[0018] The device according to the invention comprises a first evaluation unit, which is suitable and designed to analyze deviations between the signals of the detector unit and reference values. The device comprises a second evaluation unit, which is configured to analyze the milk for its constituents based on signals from the detector unit. A particularly preferred embodiment is one in which the first evaluation unit and the second evaluation unit form a single unit.

[0019] To evaluate the deviations between the detector unit signals and the reference values, an evaluation algorithm can be created using machine learning. To create the evaluation algorithm, signals from the detector unit, along with corresponding reference values, are fed into the machine learning program. The reference values ​​can be obtained, for example, by determining them through preliminary investigations.

[0020] The first and second evaluation units can be installed on a computer as part of a machine learning program. Depending on the analysis results, the device can be calibrated or adjusted. The values ​​can be determined at predefined or user-defined intervals.

[0021] Depending on the aging process of the device's components, the frequency of determining the actual values ​​can be reduced.

[0022] Furthermore, a method for analyzing milk is proposed, comprising a device with a conduit section for the milk, a light source unit which emits light into the conduit section, a detection unit (6) for detecting light, in particular spectrally resolved detection of light exiting the conduit section, and a calibration unit with a calibration element (9) having a calibration surface, wherein the detector unit and the calibration element are movable relative to each other so that the calibration surface of the calibration element (9) can be brought in front of the detector unit, with the following steps: a) placing the calibration surface (10) into a beam path of the light source unit (5), b) performing a measurement and determining a reference spectrum, c) removing the reference surface from the beam path, d) performing the measurement, e) checking and, if necessary, correcting the measured spectrum using the reference spectrum.

[0023] Correcting the measured spectrum depends particularly on the properties of the calibration surface used. If the calibration surface has known optical properties, then a wavelength-dependent reflectivity (the proportion of reflected light relative to the total light as a function of wavelength) is also known. Thus, after a measurement with such a reference surface in the beam path, the measured spectrum is stored as a reference spectrum. This reference spectrum serves as the reference for all subsequent measurements. Every calibration measurement performed under operating conditions can be compared with this reference spectrum. Preferably, this comparison is performed for each individual wavelength of the spectrum by calculating the ratio of the current value to the reference value.These multiple quotients (for the individual wavelengths) are correction factors by which the individual points of the spectrum subsequently measured on a sample are multiplied to normalize this spectrum to standard conditions. Changes in the system as well as external influences are thereby compensated for. In particular, by continuously comparing the calibration measurements with previous or the original calibration measurement, changes in the system, especially aging or wear, or fluctuating external influences, can be identified and taken into account.

[0024] If the calibration surface is highly reflective, it ideally exhibits a wavelength-independent reflectivity of approximately 100% in the relevant spectral range. This means that virtually all light, regardless of wavelength, is reflected. In this case, the reflected light corresponds exactly to the light emitted by the light source, provided there are no absorbing media in the beam path. A measured spectrum of a sample is referenced to this reference spectrum. The quotient calculated in this case (current value / reference value) represents the reflectivity of the sample for the respective wavelength. The sum of the reflectivity values ​​constitutes the reflection spectrum of the sample. The reflectivity of a sample, or its reflection spectrum, represents a material property of the sample from which essentially all system- or environment-specific influences have been eliminated.The composition of an unknown sample can also be determined from the properties of the reflection spectrum by comparison with reference values ​​(e.g. from databases).

[0025] In particular, steps a) to c) will be carried out depending on a key figure. The key figure is at least one key figure selected from a group of key figures consisting of: the number of previous milkings since the last calibration; the time interval between two consecutive milkings; the time interval since the last calibration; the number of calibrations already performed; a temperature quotient derived from the current temperature and the temperature prevailing during a previous calibration.

[0026] It is particularly preferred to perform a calibration before each measurement. This allows for the consideration of potential influences on the measurement caused by the calibration. To reduce or slow down the effort and the aging process of the components, especially the light source, calibration is preferably performed when a certain number of milkings, a certain time interval since the last calibration, and / or a certain number of calibrations have already been performed have been reached. External influences can also affect the measurement result. Preferably, the temperature of the components, especially the electronic components, is recorded and stored during the measurement. If the quotient of the current temperature of the components and a temperature from previous calibrations or measurements exceeds a certain range, this is taken into account.

[0027] Calibration is preferably also performed after cleaning, for example with hot media, especially water. It is also recommended after mechanical interventions, such as modifications, service work, or a system restart.

[0028] The invention is explained in more detail below with reference to the figures. The figures show particularly preferred embodiments, to which, however, the invention is not limited. The figures and the size relationships shown therein are schematic. They show:

[0029] Fig. 1 : a first embodiment of a device according to the invention,

[0030] Fig. 2: a second embodiment of a device according to the invention,

[0031] Fig. 3: a third embodiment of a device according to the invention and

[0032] Fig. 4: a fourth embodiment of a device according to the invention.

[0033] Fig. 1 schematically shows a first embodiment of a device 1 according to the invention for analyzing milk. The device 1 comprises a line section 2 for the milk. The line section 2 is formed within a line 3. This can be a milk line connecting a milking unit (not shown) to a milk tank (not shown). Alternatively, the line 3 can be a branch line from a line connecting the milking unit to the milk tank. This can be a so-called bypass line.

[0034] A fluid such as milk can be analyzed in line section 2 of line 3. For analyzing the milk, the device includes a monitoring unit 4. The monitoring unit 4 includes a light source unit 5. Preferably, the light source unit 5 is a halogen lamp with a continuous wavelength spectrum, which is transmitted into line section 2. The device further includes a detector unit 6 for spectrally resolving the detection of light exiting line section 2. The detection unit 6 is connected via a signal to a first evaluation unit 7.1, which is configured to analyze the milk for its constituents based on signals from the detection unit 6.

[0035] The milk can be analyzed, for example, as it exits the milking unit (not shown) and passes through line 3 and line section 2. The entire milk yield or a portion thereof can be routed through line section 2. The analysis can determine whether at least one predefined component in the milk exceeds a specific limit. Line section 2 has at least a partially transparent area.

[0036] The device 1 comprises a calibration unit with a calibration element 9. The calibration element 9 has a calibration surface 10. The calibration element 9 and the detector unit 6 are movable relative to each other, so that the calibration surface 10 of the calibration element 9 can be brought into the detection range of the detector unit 6. This is indicated in Fig. 1 by the arrow F. In the first embodiment of Fig. 1, the calibration element 9 of the calibration unit is movable, in particular displaceable.

[0037] The device includes a second evaluation unit 7.2, which is configured to analyze deviations between the signals of the detection unit 6 and reference values. The first and second evaluation units preferably form a single assembly 7.

[0038] Depending on the analysis of the second evaluation unit 7.2, the device is calibrated and / or adjusted.

[0039] In the first embodiment, as shown in Fig. 1, the detector unit 6 evaluates the reflection of light. The second embodiment according to Fig. 2 differs from the first embodiment according to Fig. 1 in that the calibration element 9 is arranged between the conductor section 2 and the detector unit 6. This has the advantage that the conductor section 2 and any possible deposits in or on the conductor section 2 have essentially no influence on a calibration process or a verification process of the calibration.

[0040] The embodiment according to Figs. 3 and 4 differs from the embodiments according to Figs. 1 and 2 in that, according to Figs. 3 and 4, the absorption of light is measured.

[0041] Calibration can be performed at predetermined time intervals. It is also possible to calibrate based on individual milking sessions or milking sessions of a group of animals. For example, if it is determined that the analytical values ​​of milk from several consecutive milking sessions of the same animal deviate from a predefined limit, calibration can be carried out.

[0042] Reference symbol list

[0043] 1 Device

[0044] 2 Line section 3 Line

[0045] 4 Monitoring device

[0046] 5 light source units

[0047] 6 detection unit

[0048] 7 Evaluation unit 7.1 First evaluation unit

[0049] 7.2 Second evaluation unit

[0050] 9 Calibration element

[0051] 10 calibration area

Claims

Claims 1. Device (1) for analyzing milk, comprising: a conduit section (2) for the milk, a light source unit (5) which emits light into the conduit section (2), a detection unit (6) for detecting light, in particular spectrally resolved detection of light, which emerges from the conduit section (2), a calibration unit with a calibration element (9) which has a calibration surface (10), wherein the detector unit (6) and the calibration element (9) are movable relative to each other so that the calibration surface (10) of the calibration element (9) can be brought in front of the detector unit, and in particular a first evaluation unit (7.1) which is configured to analyze deviations between the signals of the detection unit (6) and reference values, a second evaluation unit (7.2) which is configured to analyze the milk for constituents on the basis of signals from the detection unit (6).

2. Device (1) according to claim 1, wherein the detector unit (6) is stationary and the calibration element (9) is pivotable, in particular rotatable.

3. Device (1) according to claim 2, wherein the detector unit (6) is stationary and the calibration element (9) is movable.

4. Device (1) according to one of claims 1 to 3, wherein the calibration unit has several calibration elements, each with a calibration surface, wherein the calibration surfaces differ by their color.

5. Device (1) according to one of claims 1 to 3, wherein the calibration element has at least two calibration surfaces, the calibration surfaces being distinguished by their color.

6. Device according to claim 4 or 5, wherein the colored calibration surfaces can be selectively brought in front of the detector unit (6).

7. Device according to at least one of claims 1 to 6, wherein a first evaluation unit (7.1), which is configured to analyze deviations between the signals of the detection unit (6) and reference values, and a second evaluation unit (7.2), which is configured to analyze the milk for constituents on the basis of signals from the detection unit (6), form a single unit.

8. Arrangement comprising: a milking device, a device (1) for analyzing milk, comprising a conduit section (2) for the milk, a light source unit (5) which emits light into the conduit section (2), a detection unit (6) for detecting light, in particular spectrally resolved detection of light, which emerges from the conduit section (2), a calibration unit with a calibration element (9) which has a calibration surface (10), wherein the detector unit (6) and the calibration element (9) are movable relative to each other so that the calibration surface (10) of the calibration element (9) can be brought in front of the detector unit (6), and in particular a first evaluation unit (7.1) which is configured to analyze deviations between the signals of the detection unit (6) and reference values, a second evaluation unit (7.2) which is configured to analyze the milk for constituents on the basis of signals from the detection unit (6).wherein the milking device is connected to the line section (2) of the device (1).

9. Arrangement (10) according to claim 8, wherein the device (1) is configured according to any one of claims 1 to 7.

10. Method for analyzing milk, wherein a device comprises a conductor section (2) for the milk, a light source unit (5) which emits light into the conductor section (2), A detection unit (6) for detecting light, in particular spectrally resolved detection of light exiting the line section (2), a calibration unit with a calibration element (9) having a calibration surface (10), wherein the detector unit (6) and the calibration element (9) are movable relative to each other so that the calibration surface (10) of the calibration element (9) can be brought in front of the detector unit, with the following steps: a) placing the calibration surface (10) into a beam path of the light source unit (5), b) performing a measurement and determining a reference spectrum, c) removing the reference surface from the beam path, d) performing the measurement, e) checking and, if necessary, correcting the measured spectrum using the reference spectrum.

11. The method of claim 10, wherein steps a) to c) are performed depending on at least one parameter selected from a group of parameters consisting of a number of previous milkings since the last calibration; a time interval between two successive milkings; a time interval since the last calibration; a number of calibrations already performed; a temperature quotient formed from a current temperature and a temperature that was formed during a previous calibration.

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