Measurement device including a fitting with a flow

Abstract

The invention relates to a measuring apparatus including a fitting having a flow channel and a method of operating the same. The modular flow measurement device (40) includes a controller (74), a third module having an optical sensor (35) connected to the controller (74), a fourth module having a galvanic sensor (37) connected to the controller (74).

Description

Technical Field

[0001] The present invention relates to a module of a modular flow device, a modular flow measurement device, and an operation method thereof. Background Art

[0002] Optical sensors or amperometric sensors can be used to determine the concentration of dissolved substances in a measurement medium. However, due to legal regulations, the measured values of amperometric sensors must be traced back to standardized measured values of chemical reactions that cause coloring. Then the coloring can be evaluated using an optical system. Then the measured values can be compared or calibrated by an amperometric sensor. Measuring using an optical sensor has the following disadvantages. In the case of changes in environmental effects, it has cross-sensitivity to substances other than the actual substance to be determined in the solution and requires chemicals as color indicators. Handheld devices are usually used to calibrate or compare amperometric sensors at the measurement point. This involves obtaining a sample, performing an optical measurement on the sample using a cuvette through the handheld device, and comparing it with the measured value from the amperometric sensor.

[0003] As an alternative to handheld devices, online or inline measurement devices are also known, which perform measurements in the flow of the measurement medium. In this case, batching can be performed using a color indicator, and the colored measurement medium can be conveyed through a downstream flow cell with a photometer or colorimeter. Problems arise if the color indicator causes disposal problems, for example due to toxicity or environmental damage. The measurement devices are relatively heavy laboratory equipment. The consumption of chemicals is also relatively high. In contrast, amperometric measurement does not involve any chemical consumption.

[0004] In addition, optical sensors for concentration determination are known per se. A typical example of this is the determination of chlorine content according to the DPD measurement method. To some extent, these must be performed daily in swimming pools. In smaller systems, handheld devices can be used for this purpose. In the handheld variant, the measurement medium is filled into a cuvette, mixed with N,N-diethyl-1,4-phenylenediamine, and then measured. The measurement can be performed by colorimetry or photometry. In addition, online measurement devices are known for larger swimming pools or industrial applications. Different from handheld devices, they are correspondingly heavier and are generally not transported to different measurement locations. Instead, the online measurement device is installed near the measurement location, and the measurement device has a fluid connection to the measurement location. Therefore, the measurement device is "connected to" the measurement location or sampling location, that is, online. Sampling is usually carried out via a pump. Reagents (e.g., DPD) are added to the measurement medium through a batching system integrated in the measurement device. In this case, due to more frequent measurements, the consumption of chemicals is usually higher than that using a handheld device. The common point of these two methods is that they do not measure continuously and therefore cannot be used in an automatic control loop.

[0005] Turbidity sensors for determining the turbidity of a liquid are also known. Most of them are used in the so-called scattered light method. Turbidity can be affected by different flow effects, sedimentation effects, etc. At the same time, turbidity affects concentration measurement. Therefore, it is optimal if the turbidity measurement and the concentration determination are carried out as close together in time as possible or simultaneously. In addition, in order to reduce measurement inaccuracies, it is advantageous if two measurements are carried out as far apart as possible using the same fraction of the measurement medium. Turbidimeters are calibrated using formazin, which is harmful to the environment. If inline calibration is carried out, formazin causes problems when disposing of it and when cleaning the flow cell. Summary of the Invention

[0006] Therefore, starting from the above prior art, the object of the present invention is to provide a flow measurement device by means of which inline measurement can be achieved and which reduces the above-mentioned disadvantages of the prior art.

[0007] This object is achieved by providing a third module according to the present invention.

[0008] The third module of a modular flow measurement device having a flow channel according to the present invention comprises:

[0009] - a measurement chamber having a cuvette holder for arranging a cuvette in the measurement chamber,

[0010] - a supply line,

[0011] - a discharge line,

[0012] wherein the supply line and the discharge line are connected to the measurement chamber such that a partial cross-section of the flow channel is formed,

[0013] - a transmitting element,

[0014] - a first receiving element,

[0015] - a second receiving element,

[0016] wherein the first receiving element is arranged such that a transmitted light signal path is formed between the transmitting element and the first receiving element,

[0017] wherein the second receiving element is arranged such that a scattered light signal path is formed between the transmitting element and the second receiving element.

[0018] The above object is also achieved by providing another third module according to the present invention.

[0019] The third module of a modular flow measurement device having a flow channel according to the present invention comprises:

[0020] - a measurement chamber having a cuvette holder for arranging a cuvette in the measurement chamber,

[0021] - Supply pipeline,

[0022] - Discharge pipeline,

[0023] wherein the supply pipeline and the discharge pipeline are connected to the measurement chamber such that a partial cross-section of the flow channel is formed.

[0024] - First transmitting element,

[0025] - Second transmitting element,

[0026] - Third receiving element,

[0027] wherein the third receiving element is arranged such that a transmitted light signal path is formed between the first transmitting element and the third receiving element.

[0028] wherein the third receiving element is arranged such that a scattered light signal path is formed between the second transmitting element and the third receiving element.

[0029] The above object is also achieved by providing a modular flow measurement device according to the present invention.

[0030] The modular flow measurement device according to the present invention comprises:

[0031] - Controller,

[0032] - A third module having an optical sensor connected to the controller,

[0033] - A fourth module having an amperometric sensor connected to the controller,

[0034] wherein the flow channel fluidly and sequentially connects the third module and the fourth module to each other, wherein the optical sensor has a measurement chamber, and wherein the optical sensor has a cuvette holder such that a cuvette for calibrating the optical sensor can be arranged in the measurement chamber.

[0035] The flow measurement device comprises a flow channel. The measurement medium can be guided in the flow channel.

[0036] Furthermore, the flow measurement device has an optical sensor and an amperometric sensor.

[0037] The two sensors are arranged in a fitting to measure the concentration of the measurement medium guided in the flow channel. The flow measurement device preferably determines the concentration of the substance dissolved in the medium.

[0038] The flow measurement device has a cuvette holder for calibrating the optical measurement device.

[0039] The flow measurement device according to the present invention enables a compact arrangement of sensors, which are positioned at defined intervals by means of a fitting. The term "fitting" shall be understood here as being equivalent to the flow measurement device. The fitting also provides for the transfer of the measurement medium from the optical sensor to the amperometric sensor via the flow path. Thus, the time-consuming manual transfer from the first hand-held device to the second hand-held device is eliminated and errors are further reduced.

[0040] Furthermore, the flow measurement device enables a permanent monitoring of the concentration of substances in the measurement medium, in particular via the amperometric sensor.

[0041] Another advantage compared to the prior art is that exactly the same measurement medium is compared with the amperometric sensor and thus there is no difference between the medium in the manual measurement and the medium on the amperometric sensor.

[0042] A preferred application of the flow measurement device according to the present invention is the measurement of the quality of drinking water and / or swimming pool water.

[0043] Advantageous embodiments of the flow measurement device according to the present invention are as follows.

[0044] It is advantageous if the fitting has an inlet and an outlet, the flow channel defines the flow path between the inlet and the outlet, and the amperometric sensor is arranged downstream of the optical sensor on the flow path.

[0045] It is also advantageous if the fitting has a plurality of sensor mounts for a close arrangement of the optical and amperometric sensors in the fitting, and the sensors are arranged interchangeably in the fitting. Thus, defective or inaccurate sensors can be repaired or replaced.

[0046] The flow measurement device, in particular as an in-line flow measurement device, can have a dosing module, which is arranged in the fitting, preferably in front of the optical sensor along the flow path.

[0047] In order to determine the measurement conditions or other parameters, the flow measurement device can have a pH sensor, a flow sensor, a flow indicator and / or a conductivity sensor, which are arranged in the fitting, preferably replaceably arranged in the sensor mounts of the fitting.

[0048] The fitting has a modular design and is thus adapted to the measurement variables and accuracy requirements, wherein each module of the fitting has a partial cross-section of the flow channel and each module has a sensor mount, an inlet or an outlet. If the module is considered separately, it clearly does not have a partial cross-section but has a flow channel.

[0049] The flow measurement device according to the invention can have a sensor with an optical device housing as an optical sensor in a compact manner. In the optical device housing, receiving and / or transmitting elements are arranged for emitting and / or receiving optical signals for measuring the turbidity of the measuring medium and / or for determining the concentration of substances, in particular dissolved substances, in the measuring medium.

[0050] A receiving and / or transmitting element can be provided for each signal path. However, a particularly compact design can be achieved if two or more signal paths are formed by a single transmitting element or alternatively by a single receiving element.

[0051] Furthermore, the optical sensor has a measuring chamber in which the measuring medium can be arranged, for example in a dish. The dish holder in the measuring chamber is designed to hold the device, for example spring arms for clamping the dish.

[0052] The above-mentioned receiving and / or transmitting elements are aligned or arranged around the measuring chamber such that a scattered light signal path is provided for measuring the turbidity of the measuring medium, and a transmitted light signal path is provided for determining the concentration of substances in the measuring medium.

[0053] The above-mentioned signal paths pass through the measuring chamber and are guided through the measuring medium at the same time when passing through the measuring chamber.

[0054] In this case, the transmitted light signal path extends in a straight line, while the scattered light signal path is always designed as a deflection path. Preferably, the deflection of the receiving element relative to the transmitting element and thus the arrangement or alignment is 90°. This corresponds to the so-called 90° scattering.

[0055] Measurements according to forward scattering or backward scattering can also be implemented to expand the measurement range of the turbidity sensor. For this purpose, additional transmitting or receiving elements can be provided. The typical angles relative to preferably a single corresponding receiving or transmitting element for forward or backward scattering can be 45° or 135°. The expansion of the measurement range results from the fact that increased backward scattering occurs at particularly high turbidity levels, while increased forward scattering occurs at very low turbidity levels in the case of small particle sizes.

[0056] Combining turbidity and concentration measurements in a single sensor reduces the measurement distance between the two measurements. The turbidity measurement can preferably and advantageously be used to compensate for measurement inaccuracies in the concentration measurement and / or to indicate the error tolerance of the concentration measurement.

[0057] An optical sensor can advantageously have only one transmitting element and two or more receiving elements, wherein the transmitting element is designed to emit an optical signal having two or more different wavelengths. The first wavelength among the wavelengths, for example a wavelength in the infrared range, for example a wavelength at 520 nm, can be used to measure turbidity. The second wavelength among the wavelengths, for example a wavelength in the vis range, for example a wavelength at 860 nm, can be used to measure concentration. In this case, "vis" is a common term for wavelengths in the visible light range.

[0058] Generally speaking, existing cuvette holders allow on-site calibration or in-situ calibration to be performed for both measurements. This avoids measurement uncertainties while maintaining the compact design of the measuring device.

[0059] Further advantageously and as an alternative to the above variant, an optical sensor can have only one receiving element and two or more transmitting elements, and the receiving element is designed to receive an optical signal having two or more different wavelengths. Both of these variants can achieve a compact sensor design for performing two different measurement methods. Here, the receiving module can also evaluate both the first wavelength at 520 nm and the second wavelength at 860 nm.

[0060] The receiving element at the end of the scattered light signal path can advantageously be designed to receive an infrared light signal, and at the same time it can be designed to receive a vis light signal.

[0061] In addition, the transmitting element at the start of the scattered light signal path is designed to emit an infrared light signal, and the transmitting element at the end of the transmitted light signal path is designed to emit a vis light signal.

[0062] The measuring chamber is designed to allow the measuring medium to flow through it. Additionally, the measuring chamber is suitable for receiving a cuvette that can be filled with a calibration medium, or a sealed cuvette filled with, for example, formazine.

[0063] One or more optical prisms can be arranged between the transmitting element and the receiving element along the transmitted light signal path and the measuring chamber, preferably at least three optical prisms.

[0064] The transmitting element can advantageously be designed as one or more diodes, preferably designed as an LED.

[0065] One or more of the receiving elements can advantageously be formed as a photometric detector and / or a colorimetric comparator on the transmitted light signal path.

[0066] In addition, it is also possible to provide a measuring device which includes an optical sensor according to the present invention, as well as a fluid connection between the sampling position and the optical sensor for supplying a measuring medium, and a metering device for adding reagents for colorimetric and / or photometric measurements. Due to the design according to the present invention, the measuring device can perform concentration measurements with a lower measurement error while taking into account turbidity measurements. Particularly preferably, the measurement error of the concentration measurement can be output based on the turbidity measurement. Alternatively or additionally, the turbidity measurement can be taken into account when determining the concentration measurement, for example, when compensating for sensor drift, etc.

[0067] Furthermore, according to the present invention, one of the receiving elements of the optical sensor in the transmitted light signal path is designed as a photometric detector and / or a colorimetric comparator.

[0068] The above object is also achieved by an operating method of a flow measurement device.

[0069] The method for operating the above flow measurement device according to the present invention includes:

[0070] A Calibrating the optical sensor by inserting a dish with a calibration medium into the dish holder, preferably in-situ calibration,

[0071] B Measuring the concentration of the measuring medium flowing through the flow channel by the optical sensor, and

[0072] C Comparing and / or calibrating the amperometric concentration measurement of the measuring medium flowing through the flow channel based on the measured values determined by the amperometric sensor and the measured values of the optical sensor.

[0073] Each of the steps A - C can have further sub-steps.

[0074] It is advantageous if the turbidity of the measuring medium is also preferably measured by the optical sensor. The sensors can also be used among them, especially for a plausibility check as part of a redundant measurement in case of sensor drift or measurement value jumps.

[0075] Furthermore, according to the present invention, the measured value determined by the turbidity measurement can be compared with a target value, and if the target value is exceeded, a warning regarding the measurement performance of the concentration measurement can be displayed.

[0076] Alternatively or additionally, for example, in the case of high turbidity values, if the target value is exceeded, the control device can stop the inflow of the measuring medium into the fitting, or completely close it to protect the sensor.

[0077] Alternatively or additionally, a cleaning mode for cleaning the flow channel of the fitting can be initiated based on the turbidity measurement value or according to the time series of the turbidity measurement.

[0078] Furthermore, the amperometric sensor is capable of performing permanent measurements, and the optical sensor is capable of performing colorimetric and / or photometric measurements at irregular measurement intervals or preferably at regular measurement intervals.

[0079] In the concentration measurement according to step B, in particular, a reagent can be added to the measurement medium, via which the concentration value, preferably the DPD value, is determined and compared with the amperometric sensor. The metering is preferably carried out discontinuously. BRIEF DESCRIPTION OF THE DRAWINGS

[0080] In the following, the subject matter of the present invention will be described in detail using exemplary embodiments and with the aid of the drawings. In the drawings:

[0081] Figure 1 is a schematic structure of a first variant of an optical sensor for use in a flow measurement device according to the present invention;

[0082] Figure 2 is a schematic structure of a second variant of an optical sensor for use in a flow measurement device;

[0083] Figure 3 is a cross-sectional view of the corresponding optical sensor in the optical plane;

[0084] Figure 4 is as from Figure 3 a vertical cross-sectional view of a partial view of the optical sensor; and

[0085] Figure 5a is a front view of a flow measurement device according to the present invention having the above-described optical sensor;

[0086] Figure 5b is of a flow measurement device having additional components of the flow measurement device Figure 5a a front view; and

[0087] Figure 6 is through from Figure 3 and Figure 4 a longitudinal section of the optical sensor. DETAILED DESCRIPTION

[0088] Figure 5a and Figure 5b each show the structure of a modular flow measurement device 40 according to the present invention, which device comprises a plurality of modules 31a - 31h, which are connected to one another in a medium-tight manner. Each of the modules 31a - 31h has flow channel portions which, in the assembled state, produce a flow channel 32. The flow channel 32 is in Figure 5aare shown as dashed lines passing through the respective modules 31a - 31h. The arrows shown as triangles indicate the positions of the inlets and outlets of the relevant modules. At the end, the fitting 30 has an inlet as the inlet module 33 and an outlet as the outlet module 34. The inlet module has a process connection for supplying the measurement medium - preferably a liquid - and the outlet module has a process connection for discharging the measurement medium. The inlet module 33 and the outlet module 34 define a flow path with a flow direction. This is highlighted in Figure 5a by an arrow along the flow channel 32.

[0089] Furthermore, the flow measurement device 40 has an optical sensor 35 for determining the concentration of substances contained in the measurement medium. The optical sensor is arranged in a sensor holder 36 of a module of the flow measurement device 40. The pH, which is the negative decimal logarithm of the concentration of hydronium ions in a solution, is also one of the above-mentioned substances and can, for example, be used as a litmus test.

[0090] The optical sensor 35 can determine the concentration by colorimetric and / or photometric measurement. Colorimetric measurement records the chromatogram by comparing a color reagent in the measurement medium with a reference reagent using a comparator. In contrast, a photometer does not compare chromatograms but only discrete wavelengths and their absorption or transmission through the measurement medium. Both occur in the transmitted light signal path through the measurement medium.

[0091] Furthermore, the flow measurement device 40 has an amperometric sensor 37, which is arranged in a sensor holder 38 of a module of the fitting 30. Amperometric sensors, for example for determining the concentration of disinfectants in water, have been sold by the applicant for decades. It enables the permanent measurement or monitoring of the measurement medium, especially in the above-mentioned fitting 30.

[0092] However, the determined amperometric measurement values must be traced back to the measurement values of the optical measurement. This allows the amperometric sensor to be compared with the optical sensor from time to time and / or the optical sensor to be used to calibrate the amperometric sensor. Therefore, the amperometric sensor 37 is ideally arranged downstream of the optical sensor 35 on the flow path, but can also be installed upstream.

[0093] In inline measurement, it is usually necessary to add a dye and / or a color indicator to the measurement medium for each measurement to color the substance. This is done by the metering module 39, which is ideally arranged in front of the optical sensor 35, i.e., between the optical sensor 35 and the inlet on the flow path.

[0094] Two concentration measurement methods, namely optical and amperometric, depend in many cases on the measurement conditions and the measurement medium in which the substance is dissolved. To determine these measurement conditions, the fitting optionally has one or more additional sensors. These sensors include a pH sensor 43, a conductivity sensor 41, a flow sensor and / or a flow indicator 42, which are preferably arranged in a sensor holder, particularly preferably in the relevant modules 31e - 31g of the fitting 30.

[0095] The modules 31a - 31h are connected to each other in a medium - tight manner and are preferably arranged such that they can be separated from each other by releasing a mechanical connection (e.g., a screw connection). As Figure 3 can be seen, for this purpose, the modules have a first flange 8 and a second flange 9. The modularity of the fitting allows the fitting to be extended with additional measurement sensors, for example, which enables a more precise determination of the measurement conditions and / or the measurement medium. Other additional concentration determinations are only slightly sensitive to interference. In this case, the fitting can also consist of fewer modules.

[0096] Another important parameter is turbidity measurement. The invention includes a particularly compact arrangement of an optical sensor, which combines a cuvette holder, turbidity measurement and calorimetric and / or photometric measurement in one sensor.

[0097] The use of a cuvette holder in the optical sensor, particularly in the fitting, enables in - line calibration of the optical sensor without removing the optical sensor 35 from the fitting 30.

[0098] The concentration measurement of the optical sensor can be used to calibrate or compare the amperometric sensor.

[0099] An additional optional determination of the turbidity content can be used to detect deposits, such as red or black algae, wastewater deposits, etc. Higher turbidity can also damage the measurement membrane of the amperometric sensor or lead to inaccurate measurements. Here, the flow measurement device according to the invention can also issue a warning signal against the risk of inaccurate measurements. Alternatively or additionally, the supply to the fitting 30 can be shut off by a control device to prevent further damage.

[0100] Alternatively or additionally, turbidity measurement can be used to initiate cleaning, e.g., a cleaning program, or to set a cleaning interval. Turbidity measurement can be used to indicate measurement uncertainty, e.g., in the concentration measurement of industrial water. In this case, high turbidity is associated with higher measurement uncertainty compared to low turbidity.

[0101] The combination of the two measurement methods allows reliable in - line measurement, thus reducing the sources of manual error. In addition, the amperometric sensor enables continuous and precise concentration determination with low dye consumption.

[0102] It goes without saying that turbidity can also be simply specified as an important quality parameter when examining the measuring medium.

[0103] The flow measurement device according to the invention has the particular advantage that inline measurements can be carried out without removing the sensor, in particular an optical sensor, from the fitting for its calibration.

[0104] Figures 1 to 4 The structure of an optical sensor for carrying out concentration measurement and turbidity measurement is shown, which sensor is characterized by its compact design.

[0105] Figure 1 The schematic structure of an optical sensor 1 which is used for determining the concentration and for measuring the turbidity in the measuring medium and which is used as Figure 5a or Figure 5b a part of a flow measurement device 40 is shown.

[0106] Sensors for measuring concentration based on optical principles are known in principle. The concentration measurement of one or more substances in the measuring medium can be carried out in particular by photometric measurement and / or by colorimetric measurement.

[0107] A typical example of the measurement principle is the so-called DPD measurement, which is used to determine the chlorine and / or perchlorate content in water.

[0108] The DPD measurement device can optionally be used as a handheld device for determining the chlorine content in ponds and swimming pools, where the chlorine content sometimes has to be determined several times a day due to legal requirements. For this measurement, a colored chemical must be added to the water in the dish, and the colored chemical is usually added to the measuring medium in the form of a powder or tablet. Then the dish is placed in the dish holder in the handheld device, and the dish is located in the light beam path in the handheld device.

[0109] For larger swimming pools and amusement parks, there are also so-called online systems, which are used for the continuous supply and removal of the measuring medium. In these online systems, the colored chemical is preferably added to the sample at measurement intervals, and then the measuring medium pretreated in this way is fed into the light beam path. In terms of size, such a system cannot be compared with a handheld device. The consumption of chemicals is relatively high, but due to more consistent measurement conditions, the measurement results can be obtained quickly and are not prone to errors.

[0110] Both colorimetric measurement and photometric measurement can be used to optically determine the concentration of substances in an optical sensor.

[0111] Colorimetric measurement involves the optical comparison of the color and / or color depth between a test sample of a medium and a reference (such as a color standard). This can be, for example, a color screen. A test sample of the measurement medium can be prepared by removing the test sample of the measurement medium and transferring it to a dish. Online measurement through a flow cell is also conceivable, for example, using a bypass method. The sample and the reference are compared by a comparator.

[0112] The sensor consists of two or more emission elements and only one receiving element, or alternatively of only one emission element and two or more receiving elements. This is schematically shown in Figure 1 and Figure 2 for these two variants.

[0113] A light source (for example, a light source, possibly combined with a slit diaphragm and a so-called monochromator) can be used as an emission element. For example, by using a photodiode and / or an LED as the light source, significant simplification and simultaneous miniaturization can be achieved. An LED can produce monochromatic light, that is, light in a specific wavelength. LEDs that can produce monochromatic light with multiple wavelengths are known, which is particularly advantageous for this application since turbidity measurement is performed at a different wavelength than concentration measurement.

[0114] The monochromatic light can then be directed onto a measuring dish containing the water sample. Alternatively, a flow cell can also be used. The water sample was previously colored, and the intensity of the color depends on the concentration of the substance to be identified. In the case of a flow cell, a mixing chamber is fluidly connected upstream of the measuring chamber, and the sample is added to and mixed in this mixing chamber. The dye absorbs light at a specific wavelength, and this absorption depends on the concentration of the substance to be determined in the measurement medium. The light transmitted through the measurement medium can be conducted through an interference filter such that the light is received at a defined wavelength. Due to its design, slight fluctuations in wavelength over the course of the life cycle of many light sources are normal. Finally, the light is directed to a detector. For example, a photodiode can be used for this purpose, which converts the incident light into an electrical signal. The detector and the interference filter can be part of the receiving element. The receiving element can also optionally include a photomultiplier for amplifying the received signal. Generally, the concentration of the substance can be determined according to the Lambert-Beer law.

[0115] The structures of both colorimeters and photometers are known. While a comparator is used as the receiving element in a colorimeter, in a photometer it is at least the above-mentioned detector, possibly in combination with other components such as an interference filter.

[0116] In addition to the actual optical measurement, depending on the substance to be determined, additional measurement variables can be determined, or additional reagents can be added to the measurement medium to adjust the measurement conditions. For this purpose, the flow measurement device can have additional sensors in addition to the optical sensor. For example, the DIN standardized DPD method for determining chlorine can also determine the pH value. In addition to the DPD reagent (i.e., N,N-diethyl-p-phenylenediamine), a pH indicator (such as phenol red) can also be added. A buffer reagent is also used so that the chlorine content does not affect the pH measurement. In the chlorine measurement, an optimal pH value is set.

[0117] The process of colorimetric and / or photometric measurement itself is known. Briefly, in the measurement chamber (i.e., cuvette or flow cell), first a zero comparison is made with the measurement medium without dye, and then the dye is added. Then the measurement is carried out.

[0118] Another measurement that can be performed using an optical sensor is turbidity measurement. The formazin standard is usually used for turbidity measurement.

[0119] An infrared light source can be used as the light source according to ISO 7027:1999. In this case, the infrared measurement is not affected by the color of the medium.

[0120] Alternatively or additionally, a white light source in the visible range according to US-EPA 180.1 can be used as the light source.

[0121] Scattering light measurement and transmission light measurement are known methods for measuring turbidity. In the case of this optical sensor, scattering light measurement is used.

[0122] This measurement differentiates between forward scattering, backscattering, and 90° scattering. The standard process according to 7027 and US-EPA 180.1 is 90° measurement.

[0123] However, in a very turbid medium, backscattering can also be determined at an angle between 90° and 180° (preferably 100° to 170°), for example at 135°. An additional receiver can be provided for this purpose.

[0124] Contrary to scattering light measurement, transmission light measurement records the transmitted light. This definition of transmission light measurement also applies to colorimetric and / or photometric measurement.

[0125] Figure 1 An optical sensor 1 with a single emission element 2 and two receiving elements 3 and 4 is shown.

[0126] The optical sensor 1 also has a measurement chamber 5 for arranging the cuvette or for the flow of the measurement medium. The measurement chamber can include, for example, a holder for the cuvette.

[0127] The arrangement of the transmitting element 2 and the first receiving element 4 around the measuring chamber 5 is such that a transmitted light signal path 6 is provided between the transmitting element 2 and the first receiving element 4. The first receiving element 4 is also referred to hereinafter as the transmitted light receiving element.

[0128] The arrangement of the transmitting element 2 and the second receiving element 3 around the measuring chamber 5 is such that a scattered light signal path 7 is provided between the transmitting element 2 and the second receiving element 3.

[0129] The second receiving element 3 is also referred to hereinafter as the scattered light receiving element.

[0130] The transmitting element 2 is preferably equipped to emit light signals having two different wavelengths. The transmitting element can be designed, for example, as a photodiode and / or an LED. For example, an LED can be designed as a photodiode.

[0131] In Figure 2 the optical sensor 11 has two transmitting elements 12 and 13 and a single third receiving element 14.

[0132] Similar to Figure 1 the optical sensor 1 has a measuring chamber 15 for arranging the measuring medium.

[0133] The arrangement of the first transmitting element 12 and the third receiving element 14 around the measuring chamber 15 is such that a transmitted light signal path 16 is provided between the first transmitting element 12 and the third receiving element 14.

[0134] The arrangement of the second transmitting element 13 and the third receiving element 14 around the measuring chamber 15 is such that a scattered light signal path 17 is provided between the second transmitting element 13 and the third receiving element 14.

[0135] The third receiving element 14 is equipped for evaluating two wavelengths, preferably evaluating two wavelengths simultaneously.

[0136] Figure 3 Shows Figure 1 a more detailed structure of the optical sensor 20 in a variant of

[0137] The optical sensor 20 has an optical device housing 21. An optical device carrier 22 (for example, in the form of a plastic body and / or a circuit board) is arranged inside the optical device housing. The optical device carrier 22 has a housing 25 for the light source 23 of the transmitting element. In this case, the light source 23 can be interchangeably mounted inside the optical device carrier 22. The housing 25 preferably has a stop surface 24 such that the light source 23 is at a defined distance from the measuring medium.

[0138] In addition, the optical device carrier 22 has additional housings 26 for receiving the modules 27, 28, each receiving module being part of a first receiving element and a second receiving element. The receiving modules can be designed as diodes. These housings 27, 28 also have stop surfaces 29 for forming a defined distance between the respective receiving modules 27, 28 and the measuring medium.

[0139] The optical flow cell 30 can be arranged between one or more of the receiving modules 27, 28 and the light source 23. For example, this is designed to be similar to the dish 63, just without a base, i.e., as a tube.

[0140] The receiving module 27 is part of the transmitted light receiving element, and the receiving module 28 is part of the scattered light receiving element.

[0141] An optical prism can be arranged between the receiving module 27 of the transmitted light receiving element and the light source 23 of the flow cell 30.

[0142] Figure 4 A sensor substrate with an optical device housing 21 is shown. The optical circuit board 33 can be arranged in each case at the end of the light source 23 and at each of the receiving modules 27, 28 for signal transmission, signal tapping, and / or (if required) signal processing for receiving optical signals.

[0143] In Figure 4 the sensor substrate is elongated. It has a longitudinal axis. The elongated measuring chamber 5 extends along this longitudinal axis L and is preferably provided by the optical flow cell 30.

[0144] In addition, a return channel extends radially from the measuring chamber 5 through the optical device housing 21 to the outside of the optical sensor 20.

[0145] The above-described sensors 1, 20 combine a plurality of measurement principles that are usually used separately in multiple sensors in one sensor. The sensor design is correspondingly compact. At the same time, the separate replacement of the light source and the receiver creates the possibility of simply replacing the individual components of the sensor in the event of a first fluctuation (e.g., due to aging), enabling the optical sensors 1, 20 to be repaired without problems using simple means.

[0146] In addition, the sensors 1, 20 include a control and / or evaluation unit (not shown in detail), which can be arranged outside the sensor, for example, as a transmitter head, and which allows setting the wavelength and separately turning on and / or off the operating modes "turbidity measurement on / off" or "transmitted light measurement on / off", or even allows simultaneous operation of both operating modes.

[0147] At the same time, in the case of a light source having a wavelength that can be set in a variable manner, a desired wavelength and / or a wavelength optimized for the substance to be measured can be set by the control and / or evaluation unit.

[0148] Figure 6 is a longitudinal section through an optical sensor 50 for arrangement in a flow measurement device 40. The optical sensor has an optical device housing 51 and a measurement chamber 55 formed therein. At least one transmitting element 52 and one receiving element 53 are arranged around the measurement chamber 55. A cuvette holder 54 is arranged inside the measurement chamber 55. The measurement chamber 55 can be filled with a measurement medium via a supply line 56a arranged in the optical device housing 51, and the medium can be discharged via a discharge line 56b arranged in the optical device housing. In this case, the measurement medium is introduced into the measurement chamber from the base surface of the measurement chamber 55. In this case, the supply line 56a and the discharge line 56b extend perpendicular to the base surface in some regions in order to safely remove air bubbles in the flow. In Figure 6 the context of what is mentioned or shown, the seals and channels are designed such that the formation of condensate is advantageously prevented.

[0149] An electronic device housing 57 is arranged below the measurement chamber. The optical device housing 51 and the electronic device housing 57 can also be connected integrally as housing segments to form an integral housing. The electronic device housing has an interior in which sensor electronics 58 are arranged. At the end, the electronic device housing has an electrical sensor connection 62. The measurement chamber 55 can have elastic seals, in particular flat seals 58a and 58b, on the base and / or top side, and a cuvette 63 located in the cuvette holder 54 can be placed thereon, and the flat seals 58a and 58b form part of the cuvette holder, which is in the form of a holding device for clamping the cuvette at the end, for example. The cuvette holder 54 can enable the clamping and holding of the cuvette 63. The measurement chamber 55 is axially closed by a blind plug 64 and a pressure screw 65, but other closing variants are also conceivable.

[0150] As Figures 3 to 4 shown in, the transmitting and / or receiving elements 52 and 53 can be arranged in an optical device carrier 60, such as potting compound. In addition, the transmitting and / or receiving modules 52 and 53 are connected to optical electronics 61, such as a circuit board.

[0151] The cuvette 63 is designed to be closable or closed such that, for example, a calibration medium cannot escape. It goes without saying that the measurement chamber 55 must be emptied before inserting the cuvette 63 into the cuvette holder 54.

[0152] The optical sensor can be calibrated as follows.

[0153] a) Interrupt the flow of the measurement medium through the flow path of the fitting, in particular through the flow path section of the optical sensor;

[0154] b) Turn on the optical sensor and make it accessible, and if necessary, empty the measurement chamber;

[0155] c) Optionally, clean the measurement chamber;

[0156] d) Insert the dish in the measurement chamber into the dish holder;

[0157] e) Control the measurement function to initiate calibration, e.g., via the transmitter;

[0158] f) Remove the dish from the measurement chamber of the optical sensor after calibration is completed;

[0159] g) Close the optical sensor and / or the entire fitting;

[0160] h) Set the flow rate of the measurement medium.

[0161] After performing the above calibration of the optical sensor by inserting a dish with a calibration medium into the dish holder, it is then possible to perform a concentration measurement of the measurement medium flowing through the flow channel by means of the optical sensor.

[0162] Finally, it is possible to use the measured value determined by the amperometric sensor and the measured value of the optical sensor to perform a comparison and / or calibration of the amperometric concentration measurement of the measurement medium flowing through the flow channel.

[0163] The reference measurement or cleaning is carried out automatically via the pump 72, which supplies the corresponding reagent from the storage container 73 to the dosing module via a connection on the fitting, or pumps it into the supply line (see Figure 5b )

[0164] In this case, the pump can be adjusted via the programmable logic controller 74 or PLC, via the control and / or evaluation unit, or via the transmitter. With the aid of the transmitter controller, the pump 72 can be activated as required, at time intervals, or based on the measured values from the optical sensor. It is also possible to set the control of the cleaning mode based on the measured values in the PLC or in the autonomous cleaning controller according to the degree of contamination (since an increased degree of contamination leads to a weakening of the light), such that the cleaning is activated based on a defined limit value.

[0165] List of reference signs

[0166] 1 Optical sensor

[0167] 2 Transmitting element

[0168] 3 Second receiving element

[0169] 4 First receiving element

[0170] 5 Measurement chamber

[0171] 6 Transmission light signal path

[0172] 7 Scattered light signal path

[0173] 8 First flange

[0174] 9 Second flange

[0175] 11 Optical sensor

[0176] 12 First emission element

[0177] 13 Second emission element

[0178] 14 Third receiving element

[0179] 15 Measurement chamber

[0180] 16 Transmission light signal path

[0181] 17 Scattered light signal path

[0182] 20 Optical sensor

[0183] 21 Optical device housing

[0184] 22 Optical device carrier

[0185] 23 Light source

[0186] 24 Stop surface

[0187] 25 Outer shell

[0188] 26 Outer shell

[0189] 27 Receiving module

[0190] 28 Receiving module

[0191] 29 Stop surface

[0192] 30 Optical flow cell

[0193] 31a First module

[0194] 31b Second module

[0195] 31c Third module

[0196] 31d Fourth module

[0197] 31e Fifth module

[0198] 31f Sixth module

[0199] 31g Seventh module

[0200] 31h Eighth module

[0201] 32 Flow channels

[0202] 33 Inlet module

[0203] 34 Outlet module

[0204] 35 Optical sensor

[0205] 36 Sensor bracket

[0206] 37 Current sensor

[0207] 38 Sensor bracket

[0208] 39 Batching module

[0209] 40 Modular flow measurement device

[0210] 41 Conductivity sensor

[0211] 42 Flow indicator

[0212] 43 pH sensor

[0213] 50 Optical sensor

[0214] 51 Optical device housing

[0215] 52 Emitting element

[0216] 53 Receiving element

[0217] 54 Dish bracket

[0218] 55 Measurement chamber

[0219] 56a Supply pipeline

[0220] 56b Discharge pipeline

[0221] 57 Electronic device housing

[0222] 58 Sensor electronics

[0223] 58a Flat seal

[0224] 58b Flat seal

[0225] 60 Optical device carrier

[0226] 61 Optical electronics

[0227] 62 Sensor connection

[0228] 63 Dish

[0229] 64 Blind plug

[0230] 65 Pressure Screw

[0231] 72 Pump

[0232] 73 Storage Container

[0233] 74 Controller

Claims

1. A third module (31c) of a modular flow measurement device (40) having a flow channel (32), comprising: - a measuring chamber (55) having a cuvette holder (54) for arranging a cuvette (63) in the measuring chamber (55), - supply line (56a), - discharge line (56b), wherein the supply line (56a) and the discharge line (56b) are connected to the measuring chamber (55) so as to form a partial cross section of the flow channel (32), - Transmitting element (2), - a first receiving element (4), - a second receiving element (3), The first receiving element (4) is arranged so that a transmission light signal path (6) is formed between the transmitting element (2) and the first receiving element (4). The second receiving element (3) is arranged so as to form a scattered light signal path (7) between the transmitting element (2) and the second receiving element (3).

2. A third module (31c) of a modular flow measurement device (40) having a flow channel (32), comprising: - a measuring chamber (55) having a cuvette holder (54) for arranging a cuvette (63) in the measuring chamber (55), - supply line (56a), - discharge line (56b), wherein the supply line (56a) and the discharge line (56b) are connected to the measuring chamber (55) so as to form a partial cross section of the flow channel (32), - a first radiating element (12), - a second radiating element (13), - a third receiving element (14), The third receiving element (14) is arranged so that a transmission light signal path (16) is formed between the first transmitting element (12) and the third receiving element (14). The third receiving element (14) is arranged so as to form a scattered light signal path (17) between the second transmitting element (13) and the third receiving element (14).

3. The third module (31c) according to claim 1 or 2, wherein: The module (31c) has a first flange (8) and a second flange (9), wherein the supply line (56a) opens into the first flange (8) and the discharge line (56b) opens into the second flange (9), wherein the first flange (8) and the second flange (9) are suitable for connecting the module (31c) to another module (31a, 31b, 31d, 31e, 31f, 31g, 31h) of the modular flow measuring device (40).

4. The third module (31c) according to any one of the preceding claims, wherein The vessel holder ( 54 ) can be closed by a blind plug ( 64 ).

5. A modular flow measurement device (40), comprising: - Controller (74), - a third module (31c) having an optical sensor (35) connected to the controller (74), - a fourth module (31d) having an amperometric sensor (37) connected to the controller (74), wherein a flow channel (32) fluidically connects the third module (31c) and the fourth module (31d) to one another sequentially, wherein the optical sensor (35) has a measuring chamber (55), wherein the optical sensor (35) has a dish holder (54) so ​​that a dish (63) for calibrating the optical sensor (1, 11, 20, 35, 50) can be arranged in the measuring chamber (55).

6. The modular flow measurement device (40) according to any one of the preceding claims, wherein The modular flow measurement device (40) has a metering module (39) which is arranged along the flow path in front of the optical sensor (1, 11, 20, 35, 50).

7. The modular flow measurement device (40) according to any of the preceding claims, wherein The modular flow measurement device (40) has a replaceable pH sensor (43) in the fifth module (31d), a flow indicator (42) in the seventh module (31g) and / or a replaceable conductivity sensor (41) in the sixth module (31f).

8. The modular flow measurement device (40) according to any one of the preceding claims, wherein Each module (31a-31h) has a partial cross-section of the flow channel (32), and each module (31a-31h) has a sensor bracket (36, 38), an inlet or an outlet.

9. The modular flow measurement device (40) according to any one of the preceding claims, wherein The optical sensor (1, 11, 20, 50) has an optical housing (21) in which receiving and / or transmitting elements (2-4, 12-14, 23, 25, 26) are arranged for transmitting and / or receiving light signals, in each case for measuring the turbidity of a measurement medium and / or for determining the concentration of a substance in the measurement medium, and the optical housing (21) has a measurement space (5, 15) in which the measurement medium can be arranged, wherein the receiving and / or transmitting elements (2-4, 12-14, 23, 25, 26) are aligned around the measurement space (5, 15) so that a scattered light signal path (7, 17) is formed for measuring the turbidity of the measurement medium and a transmitted light signal path (6, 16) is formed for determining the concentration of a substance in the measurement medium.

10. The modular flow measurement device (40) according to any one of the preceding claims, wherein The optical sensor (1) has only one transmitting element (2, 23) and two or more receiving elements (3, 4, 25, 26), wherein the transmitting element (2, 23) is designed to transmit a light signal having two or more different wavelengths, in particular a first wavelength at 520 nm and a second wavelength at 860 nm, or The optical sensor (11) has only a third receiving element (14) and two or more transmitting elements (12, 13), wherein the third receiving element (14) is designed to receive light signals having two or more different wavelengths, in particular a first wavelength at 520 nm and a second wavelength at 860 nm.

11. The modular flow measurement device (40) according to any one of the preceding claims, wherein The receiving element (3, 14, 27) at the end of the scattered light signal path (7, 17) is designed to receive an infrared light signal, and the receiving element (3, 14, 26) at the end of the transmitted light signal path (6, 16) is designed to receive a visible light signal, or The emitting element (2, 13, 23) at the start of the scattered light signal path (7, 17) is designed to emit an infrared light signal, and the emitting element (2, 12, 23) at the end of the transmitted light signal path (6, 16) is designed to emit a visible light signal.

12. The modular flow measurement device (40) according to any one of the preceding claims, wherein The measuring chamber (5, 15, 55) has the cuvette holder (54) and preferably has a cuvette (63) which can be filled with a measured medium and / or a flow cell which is designed to allow a permanent flow therethrough.

13. The modular flow measurement device (40) according to any one of the preceding claims, wherein One of the receiving elements (4, 14, 26, 53) of the optical sensor on the transmitted light signal path (6, 16) is designed as a photometric detector and / or a colorimetric comparator.

14. A method for operating a modular flow measurement device (40) according to claim 5, wherein: The method comprises: A. calibrating the optical sensor (1, 11, 20, 50) by inserting a cuvette (63) with a calibration medium into the cuvette holder (54), preferably in situ calibration; B. the optical sensor (35) performs concentration measurement of the measurement medium conducted through the flow channel (32); and C compares and / or calibrates an amperometric concentration measurement of a measured medium conducted through the flow channel (32) based on the measured values ​​determined by the amperometric sensor (37) and the measured values ​​of the optical sensor (35).

15. The method according to claim 14, wherein: Preferably, a turbidity measurement of the measured medium is also performed by the optical sensor (35).

16. The method according to claim 15, wherein: The measured value determined by the turbidity measurement is compared with a target value and, if the target value is exceeded, a warning about the measurement performance of the concentration measurement is displayed and / or, if the target value is exceeded, a control element, in particular a pump (72) and / or a valve, stops the inflow of the measurement medium into the modular flow measurement device (40) and / or starts a cleaning mode for cleaning the flow channel (32) of the modular flow measurement device (40).

17. The method according to any one of claims 14 to 16, wherein: The amperometric sensor (37) performs permanent measurements and the optical sensor (35) performs colorimetric and / or photometric measurements at irregular or preferably regular measurement intervals.

18. The method according to any one of claims 14 to 17, wherein: During the concentration measurement according to step B, a reagent is dosed, preferably discontinuously, via which a concentration value, preferably a DPD value, is determined and compared with the amperometric sensor (37).

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