Method for sensing the properties of a liquid, and a mixer with a sensor

Abstract

1. A sensor mixer having a mixing device for mixing two or more components to produce a mixed liquid at a mixer output, and a property sensor for determining a property of the liquid, the property sensor comprising: a) a channel containing a sensing zone through which a liquid flows; b) two electrodes for generating an electric field at one or more sensing frequencies within the sensing zone; c) a data storage device containing a pre-stored set of calibration data representing previously measured calibration impedance responses at one or more sensing frequencies and at various property values ​​of the same liquid property; d) A device that repeatedly i) generating an electric field in the sensing zone between electrodes; ii) sensing the response impedance between the electrodes; iii) a device for deriving a characteristic value of the liquid property from the response impedance using a pre-stored set of calibration data representing the calibrated impedance response; The sensored mixer, wherein the characteristic sensor is in fluid communication with the mixer output such that the mixed liquid can flow from the mixer output through the sensing zone. A method for sensing a property of a liquid and a data set of calibration data representing a calibrated impedance response usable in the sensor and method are disclosed.

Description

Technical Field

[0001] The present disclosure relates to a sensor capable of determining the characteristics of a liquid, and a method for determining the characteristics of a liquid. The present disclosure also relates to a dataset that can be used in such sensors and methods.

[0002] Many industrial processes use liquid materials such as, to name a few, liquid adhesives, liquid food ingredients, liquid coolants, or liquid reaction products. The specific characteristics of such liquids vary over time. Adhesives can cure, oils can become less viscous as the temperature rises, coolants can change over time and may have a lower heat capacity than at first.

[0003] However, many industrial processes rely on the specific characteristics of the liquid being within a specified range or not having changed compared to the characteristics in the initial state.

[0004] Electrical sensors have been used for many years to determine the characteristics of liquids or to identify deviations from desired values of those characteristics. For example, U.S. Patent Application No. 2010 / 0188110A1 describes a sensor having an integrated electrode in a single sensor configuration that operates by alternating current including periodic electrical excitation signals of a plurality of frequencies each having the same amplitude to detect an analyte in a fluid.

[0005] Furthermore, U.S. Patent Application No. 2009 / 0309615A1 describes a method for measuring the mixing ratio of a substance mixture consisting of at least two substances, the substance mixture being moved within the measurement range of a capacitance sensor, and in particular, moved over or through the sensor, and the mixing ratio being determined from the change in capacitance of the sensor caused by the substance mixture.

[0006] However, there is still a need for sensors that can sense values of liquid characteristics higher than the mixing ratio.

[0007] In a first aspect, this disclosure provides a sensor-equipped mixer having a mixing device for mixing two or more components to produce a mixed liquid at the mixer output section, and a characteristic sensor for determining characteristic values ​​of the liquid's properties, wherein the characteristic sensor is a) A channel including a sensing zone through which liquid flows when in use, and b) Two electrodes for generating an electric field of one or more sensing frequencies within the sensing zone, c) A data storage device including a pre-stored set of calibration data representing calibration impedance responses previously measured at one or more sensing frequencies and with various characteristic values ​​of the same liquid properties, d) A characteristic value derivator electrically connected to an electrode, which repeatedly i) While the liquid flows through the sensing zone, an electric field of one or more sensing frequencies is generated between the electrodes within the sensing zone. ii) While the liquid flows through the sensing zone and an electric field is present, the response impedance between the electrodes is sensed at one or more sensing frequencies. iii) A characteristic value derivator that is operable to derive characteristic values ​​of the liquid's properties from the response impedance using a pre-stored set of calibration data representing the calibration impedance response.

[0008] Characteristic sensors included in a sensor-equipped mixer as described herein may be used to sense the properties of the liquids resulting from the mixing process. These sensors may also be used to sense the properties of input liquids for the mixing process or industrial production process. Advantageously, a separate characteristic sensor for each input liquid is placed immediately before the mixer. Data from these characteristic sensors measuring the input liquids can be processed together with data from characteristic sensors measuring the mixed liquid, for example, in an integrated material property monitoring system. For example, if a liquid composition is mixed from three input liquids, the properties of each of the three liquids before mixing can be determined using three characteristic sensors located at the outlets of the three containers containing the three input liquids. This is useful for quality control and can reduce waste that might otherwise result from one of the input liquids being outside of specified properties.

[0009] The sensor in the sensor-equipped mixer according to this disclosure can determine various properties of a liquid, such as the mixing ratio of a two-component adhesive, the curing state of a curable composition, or the aging state. The number of previously varied properties to establish a set of calibration data representing the calibration impedance response previously measured at various characteristic values ​​determines the number of properties that can be later determined by the characteristic sensor. A pre-stored set of calibration data representing the calibration impedance response previously measured at one or more sensing frequencies and at various characteristic values ​​of the liquid's properties forms or represents a multidimensional data field specific to the liquid. This data field allows a characteristic value derivator to determine the value of the liquid's properties from the actually measured response impedance.

[0010] Liquids have many properties, such as viscosity, density, color, content of volatile components, water content, chemical composition, and boiling point, as well as their aging state, curing state in the case of liquid curable compositions, or mixing ratio in the case of a mixture.

[0011] It is not always possible to determine all properties of a liquid using the sensors or methods described herein. However, since certain properties of a particular liquid vary with time and / or other parameters, the response impedance in the characteristic sensors described herein also varies with time and / or other parameters. The values ​​of these properties can be derived through the characteristic sensors.

[0012] Variations over time include variations in properties between different manufacturing lots of a liquid. Therefore, the property sensors described herein can be used to detect differences in preferred liquid properties (e.g., chemical composition) between later and earlier manufacturing lots of a liquid.

[0013] The term “property” of a liquid as used in this disclosure is not particularly limited. In certain embodiments, the property is the mixing ratio of two or more components of the liquid. In some of these embodiments, the liquid is a two-component adhesive, and the property of the liquid is the mixing ratio of the components. In other embodiments, the property is the degree of curing or curing state. In some of these embodiments, the liquid is a curable composition, and the property of the liquid is the degree of curing of the composition.

[0014] In other embodiments, the characteristic is the degree of aging or the state of aging. In some of these embodiments, the liquid is an aging liquid, i.e., a liquid whose specific characteristics change over time after it is produced. The characteristic sensor can determine the change in the response impedance of the aging liquid after some aging by comparing it with the response impedance of the same liquid recorded at specific times before and after aging. Thereafter, the characteristic sensor can determine the degree of aging or the state of aging of the liquid.

[0015] The properties of a liquid can take on a variety of values. For example, the "dynamic viscosity" of the liquid "water" can take on values ​​such as 1.30 mPa.s or 0.31 mPa.s. Such values ​​are referred to as characteristic values ​​in this specification.

[0016] Certain properties do not necessarily have to be related only to numerical property values. For example, the property "degree of hardening" may have property values ​​such as "unhardened," "partially hardened," or "fully hardened." For example, the property "curing state" may have property values ​​such as "unhardened" or "fully hardened."

[0017] The liquid according to this disclosure may be a viscous liquid.

[0018] The liquid may be a fluid liquid, regardless of its viscosity. The liquid may be a liquid that flows continuously.

[0019] In certain embodiments, the liquid is a liquid adhesive. In some of these embodiments, the liquid is a curable liquid adhesive. In some of these embodiments, the liquid is a curable two-component liquid adhesive. "Two-component" means that the adhesive consists of a first component and a second component, which are mixed, for example, in a static mixer or a dynamic mixer to form the adhesive.

[0020] In other embodiments, the liquid is a dielectric fluid such as a void filler, sealant, or 3M® Novec® high-performance liquid, a thermally conductive interface material such as a thermally conductive void filler, or a liquid chemical composition for producing any of the aforementioned liquids, or includes them.

[0021] The channel of the characteristic sensor facilitates the flow of liquid through the sensing zone. The liquid can flow through the channel and the sensing zone.

[0022] A channel can define the direction of liquid flow. A channel may have a cross-section at any point along the flow direction, for example, a cross-section determined to be perpendicular to the flow direction. A channel may have a length measured along the flow direction. The cross-section may be constant over the length of the channel. For example, a channel may have a circular, elliptical, rectangular, or square cross-section over its length, and the cross-section is constant over the length of the channel.

[0023] The channel may be, for example, a passage in a static mixer or a passage in an extruder, through which a liquid can flow.

[0024] The channel of the property sensor of the sensor-equipped mixer according to the present disclosure includes a sensing zone. When the property sensor is in use, the liquid flows through the sensing zone. The electric field generated by the property value detector via the electrodes extends into the sensing zone. The liquid flowing through the sensing zone is exposed to the electric field and provides a specific impedance to the electric field between the electrodes.

[0025] The property sensor may be designed such that the sensing zone is defined by the channel.

[0026] In certain embodiments, the sensing zone is a longitudinal portion of the channel.

[0027] The shape of the electrodes is not very important as long as it can generate an electric field of appropriate strength and geometry in the sensing zone. The strength and geometry of the electric field must be selected such that a sufficient electric field strength for determining the response impedance is available in the sensing zone.

[0028] In certain embodiments, the sensing zone is disposed between the electrodes. Such a configuration can provide a stronger electric field in the sensing zone and provide a more accurate sensing of the response impedance.

[0029] In certain embodiments, the electrodes are opposing parallel plates, forming a parallel plate capacitor. The dielectric of this parallel plate capacitor may include the liquid flowing through the sensing zone.

[0030] In certain other embodiments, the electrodes are parallel plates arranged side by side in the same geometric plane or include parallel plates. This is an electrode arrangement that may save space and further enables both electrodes to be disposed on the same side of the sensing zone. In such an arrangement, the fringe electric field between the electrodes can extend into the sensing zone.

[0031] In certain embodiments, the electrodes are positioned outside the channel. This can help avoid direct contact between the liquid and the electrodes and protect the electrodes from mechanical or chemical influences from the liquid.

[0032] In certain other embodiments, the electrodes are positioned inside the channel. In some of these embodiments, the electrodes are immersed in a liquid. Such arrangements may provide a stronger response impedance signal.

[0033] In certain embodiments, one or both electrodes are positioned to be in contact with the liquid as it flows through the sensing zone. In this case as well, such an arrangement may provide a stronger response impedance signal and less noise.

[0034] In certain embodiments, the electrode includes a flat plate oriented parallel to the direction of liquid flow at the electrode location. The parallel arrangement can result in a smoother flow of liquid at the electrode location and less mechanical force acting on the electrode. In some of these embodiments, each electrode comprises a flat plate oriented parallel to the direction of liquid flow at the respective electrode location.

[0035] In certain embodiments, the electrodes are conductive paths or conductive patches on the front surface of a printed circuit board (PCB). Areas on the front surface of the PCB adjacent to the conductive paths or conductive patches forming the electrodes may be covered with a further separate conductive layer that acts as a shield, restricting the effective capacitor plane electrode area to the area of ​​the conductive paths or conductive patches. Similar conductive layers can be applied to the back surface of the PCB to form a shield that helps reduce the influence of external electric fields on the electrodes, thereby improving the overall accuracy of the characteristic sensor.

[0036] The characteristic sensor in a sensor-equipped mixer according to this disclosure may have additional electrodes for generating electric fields of one or more sensing frequencies within the sensing zone. The characteristic sensor in a sensor-equipped mixer according to this disclosure may have a third electrode for generating electric fields of one or more sensing frequencies within the sensing zone. The characteristic sensor in a sensor-equipped mixer according to this disclosure may have a third and a fourth electrode for generating electric fields of one or more sensing frequencies within the sensing zone. The additional electrodes may help to reinforce or shape the electric field within the sensing zone. This may result in a stronger response impedance signal and improved accuracy in sensing the properties of the liquid. The additional electrodes may also allow for an increase in the maximum allowable flow rate of the liquid through the sensor.

[0037] Therefore, in certain embodiments, the characteristic sensor comprises a third electrode for generating an electric field of one or more sensing frequencies within the sensing zone. The third electrode may have a voltage different from the voltages of the two electrodes. In certain embodiments, the characteristic sensor comprises a third electrode and a fourth electrode for generating an electric field of one or more sensing frequencies within the sensing zone. The third electrode and / or the fourth electrode may have a voltage different from the voltages of the two electrodes.

[0038] The electric field between the electrodes is an alternating current (AC) electric field. This electric field induces a displacement current in the liquid within the sensing zone. The response impedance can be sensed by accurately measuring the voltage applied between the electrodes and the resulting current in the time domain. To sense the response impedance at various sensing frequencies, the electric field generated between the electrodes within the sensing zone may be generated such that, for example, it oscillates at a first sensing frequency with a first constant amplitude over a specific time over which the response impedance at the first sensing frequency is sensed, and then oscillates at a second sensing frequency with a second constant amplitude over a specific time over which the response impedance at the second sensing frequency is sensed. If a third sensing frequency is used, the electric field is made to oscillate at the third sensing frequency with a third constant amplitude over a specific time over which the response impedance at the third sensing frequency is sensed, and so on.

[0039] Instead of sequentially generating sensing frequencies and separately measuring the response impedance at each sensing frequency, all amplitudes and all desired sensing frequencies can be generated simultaneously and superimposed on each other, for example by Fourier synthesis, to form a single pulse or "burst" of a specific shape in the time-amplitude diagram. The resulting overlay of many frequencies can be a type of electromagnetic noise. If multiple sensing frequencies are superimposed on each other for a long period of time, they can form a repeating shape in the time-amplitude diagram.

[0040] When multiple sensing frequencies are superimposed on each other, the resulting response impedance signal can be separated by frequency, i.e., filtered, for example by Fourier analysis, in order to obtain the response impedance for each individual sensing frequency.

[0041] Depending on the type of liquid, useful sensing frequencies may be, for example, 32 Hz, 100 Hz, 1000 Hz, 5000 Hz, or 8000 Hz. Generally, sensing frequencies can range from 1 Hz to 10000 Hz (10 kHz), or even up to 100000 Hz (100 kHz). In certain preferred embodiments, the sensing frequency is 200 Hz to 2000 Hz, because small differences in the values ​​of key properties of a particular industrial liquid result in particularly large differences in response impedance within this frequency range.

[0042] The voltage across the electrodes can range from 0.1 volts to 100 volts. This voltage is typically between 1 volt and 20 volts, preferably between 1 volt and 10 volts. Voltages greater than 1 volt have been found to provide an acceptable signal-to-noise ratio for certain liquids. Voltages less than 100 volts are well below the dielectric strength of many typical liquids that may be used in the characteristic sensors described herein, assuming a typical distance of a few millimeters between the electrodes.

[0043] In certain embodiments, the amplitude of the electric field is between 100 volts / meter and 20,000 volts / meter. Such electric field strengths at sensing frequencies within the aforementioned range have been found to facilitate reliable sensing of response impedance with appropriate accuracy. These amplitudes have been found to be low enough to avoid electrolysis in liquids and associated changes in chemical composition, but high enough to obtain a sufficiently strong response impedance signal for many liquids.

[0044] The values ​​of a liquid's properties are obtained using a set of calibration data representing pre-stored calibration impedance responses. Calibration data representing a set of calibration impedance responses for a specific property of a particular liquid can be obtained, for example, by recording the impedance response at different sensing frequencies measured with the same liquid in the same or identical property sensor for each of several values ​​of the property. The impedance response thus measured is the calibration impedance response, which is later used during "real" measurements to relate the response impedance of the "real" measurement to the calibration impedance response and derive the property value from this relationship. Alternatively, the impedance response thus measured can be used, for example, to compute a set of parameters that mathematically describe a multidimensional data field, such as a set of polynomials or a parameterized multidimensional surface, which can then be used to derive the liquid's property value from the measured response impedance. The parameters may be derived in a calibration procedure using the same liquid in the property sensor, and these parameters may be stored on a data storage device and used during measurement to compute polynomials or multidimensional surfaces at specific response impedance values.

[0045] In general, the calibration impedance response can vary depending on other parameters, such as the liquid's properties, the sensing frequency, the liquid's temperature within the sensing zone, and, if the liquid is a curable composition, the degree of curing. Therefore, the calibration impedance response (CIR) is a function of several variables. CIR = f(characteristic value, sensing frequency, temperature, ...) Therefore, the values ​​of the liquid's properties are inverse functions. Characteristic value = f-1(CIR, sensing frequency, temperature, ...)

[0046] To obtain a set of calibration data representing the calibration impedance response, all variables are varied simultaneously or sequentially within their respective intervals in a controlled manner that reflects the possible values ​​of these variables in the measurement. For each combination of variables, the calibration impedance response is recorded, ultimately yielding a multidimensional data field. This data field is a set of calibration impedance responses that will later be used to derive liquid characteristic values ​​from the response impedances acquired in the measurement, or it is used to compute a set of calibration data representing these calibration impedance responses, such as a set of parameters for a set of polynomials that fit the calibration impedance response. In this step, some variables are determined and fixed during the measurement so that ultimately only the unknown variable becomes a characteristic value. This unknown variable can then be derived from the set of calibration impedance responses, or from the set of calibration data representing the calibration impedance response, by considering the fixed or decision values ​​of the other variables, as well as the impedance responses recorded in the measurement.

[0047] During the calibration process, the calibration impedance response corresponding to a particular response impedance may not be recorded. In such cases, interpolation may be performed on the set of calibration impedance responses to calculate the characteristic value for the particular response impedance, or a set of calibration data representing the calibration impedance response may be used to calculate the characteristic value for the particular response impedance.

[0048] As used herein, the term “interpolation process” refers to any kind of mathematical process that provides a characteristic value of response impedance between two or more calibration impedance responses in a set of calibration impedance responses represented by a set of calibration data.

[0049] The calibration impedance response can be represented by a set of calibration data, just as a set of z values ​​across the xy plane can be represented by a set of parameters a, b, c of a two-dimensional polynomial pa, b, c(x,y) that fits or approximates these z values. Therefore, the calibration data may be parameters of a function or set of functions that includes, approximates, or best fits the calibration impedance response previously measured in the calibration procedure.

[0050] Alternatively, the calibration impedance response may be expressed by itself, for example. In such cases, it may be beneficial to use the calibration impedance response itself rather than fitting or approximating the measured calibration impedance response by a function.

[0051] To speed up the interpolation process, the set of calibration impedance responses may take the form of a multidimensional data field, which is represented by a set of calibration data. The calibration impedance response may take the form of a parameterized multidimensional data field represented by a set of calibration data. The parameters in the parameterized multidimensional data field may be response impedances. Alternatively or additionally, the parameters in the parameterized multidimensional data field may be the temperature of the liquid in the sensing zone.

[0052] Generally, different liquids, under otherwise identical conditions, have different values ​​of certain properties. To optimize sensing accuracy, the calibration impedance response should be generated using a liquid whose properties are identical, i.e., sufficiently similar, to the liquid that will be sensed later. However, in certain embodiments, the calibration impedance response may be generated by using different liquids and mathematically adjusting the impedance values ​​obtained for the difference between the liquids to obtain a set of calibration impedance responses.

[0053] In general, different characteristic sensors will output slightly different values ​​of a particular characteristic, even under the same liquid and otherwise identical conditions. This is due, for example, to uncontrollable tolerances in the geometry of the channel and electrodes. To improve sensing accuracy, a set of calibration impedance responses should be generated using the characteristic sensors later used to sense the response impedance, or using identical characteristic sensors. However, in certain embodiments, the calibration impedance response may be generated by using different characteristic sensors and mathematically adjusting the impedance values ​​obtained for the difference between the characteristic sensors to obtain the calibration impedance response.

[0054] The set of calibration data representing the calibration impedance response is stored in a data storage device before the characteristic value derivator uses the calibration data representing the calibration impedance response and the response impedance of the current measurement to derive the characteristic value of the liquid.

[0055] A set of calibration data representing the calibration impedance response may be stored in a data storage device in a separate calibration process some time before the industrial production process is carried out.

[0056] A pre-stored set of calibration data representing the calibration impedance response is stored, for example, in a data storage device in digital format. The data storage device containing the pre-stored set of calibration data representing the calibration impedance response may be, for example, random access memory (RAM), a hard disk, USB removable media, an optical disc such as a CD-ROM or DVD, a cloud server, a network server, a computer on a network, or any other suitable storage device.

[0057] The characteristic value derivator accesses a data storage device to retrieve a set of calibration data representing the calibration impedance response stored therein. Therefore, the data storage device is operably connected to the characteristic value derivator. The data storage device may be operably connected to the characteristic value derivator at least before the characteristic value derivator derives the characteristic value of the liquid from the response impedance. The data storage device may be operably connected to the characteristic value derivator at least while the characteristic value derivator derives the characteristic value of the liquid from the response impedance.

[0058] The data storage device may include a characteristic value derivator. The data storage device may be located inside the characteristic value derivator. Alternatively, the data storage device may be located outside the characteristic value derivator, for example, separately from the characteristic value derivator.

[0059] In certain embodiments, the characteristic value derivator is a computerized characteristic value derivator. The computerized characteristic value derivator has a digital processor and memory. In such embodiments, the data storage device may be a mass storage device or removable medium connected to the computerized characteristic value derivator. The computerized characteristic value derivator may be operably connected to a mixer or extruder through which a liquid flows into a channel.

[0060] The characteristic value derivator performs at least the functions of i) generating an electric field between electrodes, ii) sensing the response impedance, and iii) deriving the characteristic value of a liquid from the response impedance using a set of calibration data representing the calibration impedance response. Thus, the characteristic value derivator may include a first functional unit for generating voltages of one or more frequencies between electrodes.

[0061] The characteristic value derivator may include a second functional unit for sensing impedance. The second functional unit may include a current sensor.

[0062] The characteristic value derivator may include a third functional unit for deriving characteristic values ​​from a set of calibration data representing response impedance and calibration impedance response. This third functional unit may be a computerized functional unit, i.e., having a digital processor and memory. In such embodiments, the data storage device may be a mass storage device or removable medium connected to the computerized third functional unit. The computerized third functional unit may be operably connected to a mixer or extruder through which a liquid flows into a channel.

[0063] An electric field is generated between two electrodes and extends within the sensing zone. Depending on the geometric shape of the electrodes and their relative arrangement, the electric field may extend into areas not necessarily geometrically located between the electrodes.

[0064] The electric field may be homogeneous or may contain homogeneous portions. For example, the electrodes may be flat, of equal size, and parallel to each other, forming a conventional flat-plate capacitor. In general, the electric field does not need to be homogeneous in the sensing zone; therefore, the electric field may be homogeneous or heterogeneous in the sensing zone.

[0065] Generally, electrical impedance is a frequency-dependent resistance, i.e., the ratio of voltage to current, and is a measure of resistance to time-varying current in an electrical circuit. The characteristic value derivator in the characteristic sensor of the sensor-equipped mixer according to the present invention generates an AC electric field between electrodes, thereby generating an AC voltage, and senses the response impedance by sensing the current generated by the applied AC voltage. By dividing the voltage at the sensing frequency by the current at the sensing frequency, the impedance at the sensing frequency is obtained.

[0066] A characteristic derivator can derive characteristic values ​​of a liquid's properties from its response impedance using a pre-stored set of calibration data representing the calibration impedance response. In one embodiment, the characteristic value derivator operates to use, for example, the dependency of the calibration impedance response to the characteristic value. This dependency is reflected in the calibration impedance response and the set of calibration data representing the calibration impedance response.

[0067] Each set of parameters—CIR, sensing frequency, temperature, and other parameters—defined a point in a multidimensional parameter space, where the relevant values ​​of the characteristics existed during the calibration process. After calibration, actual measurements may be performed with different parameters, e.g., different sensing frequencies, different temperatures, etc., resulting in different response impedances (MRI). To identify characteristic values ​​using the measured response impedance (MRI), Characteristic value = f-1(MRI, sensing frequency, temperature, ...) The parameters of the calibration process may need to be interpolated to match the parameters of the measurement, so that characteristic values ​​can be derived at precise points within the parameter space in which the measurement was performed.

[0068] Next, the calibration data represents the calibration impedance response, i.e., the parameter-dependent CIR value. CIR = f(characteristic value, sensing frequency, temperature, ...)

[0069] Therefore, the calibration data can be useful in determining the inverse function f-1, or the CIR value closest to the measured response impedance value MRI, and the relevant values ​​of the liquid's properties. If the interpolated values ​​of the parameters are indicated with an asterisk, the characteristic values ​​can be identified by using the inverse function with the interpolated values. Characteristic value = f-1(CIR*, sensing frequency*, temperature*, ...)

[0070] The CIR values ​​obtained during calibration are interpolated to yield the MRI sensed during measurement, the sensing frequencies used during the calibration process are interpolated to yield the sensing frequencies used during measurement, and the temperatures used during the calibration process are interpolated to yield the temperatures in the actual measurement. Thus, the values ​​of the liquid properties can be derived from the response impedance using a pre-stored set of calibration data representing the calibration impedance response.

[0071] Neither f nor its reciprocal f-1 may be explicitly known. Instead, a multidimensional data field representing f(CIR, ...) can be numerically examined to find the best match value of f-1(MRI, ...). The multidimensional data field may be the result of a mathematical operation such as regression, minimization, or interpolation. This mathematical operation can use calibration impedance response data measured in a previous calibration run as input.

[0072] In certain embodiments, the characteristic value derivator comprises a machine learning device capable of deriving characteristic values ​​of a liquid's properties from response impedances using a pre-stored set of calibration impedance responses. In some of these embodiments, the pre-stored set of calibration impedance responses may be, or may be, a set of training data for training the machine learning device.

[0073] Finding the best match value may involve interpolation between several data points within a set of calibration impedance responses, or between data points within a set of calibration data. For example, in calibration, the mixing ratio may be determined in two calibration impedance responses. In measurement, the response impedance may fall between these two calibration impedance responses. To determine the mixing ratio in measurement, the resulting mixing ratio is obtained by interpolating between the mixing ratios of each calibration impedance response.

[0074] In certain embodiments, using a pre-stored set of calibration data representing a calibration impedance response includes comparing a measured response impedance with the calibration impedance response. In certain embodiments, using a pre-stored set of calibration impedance responses includes determining the calibration impedance response that is closest to the response impedance. In certain embodiments, using a pre-stored set of calibration data representing a calibration impedance response includes determining the characteristic value of a liquid property by interpolating between two characteristic values ​​of the property included in the calibration impedance response represented by the set of calibration data.

[0075] In certain embodiments, using a pre-stored set of calibration data representing a calibration impedance response includes identifying a calibration impedance response data point whose response impedance is at least closest to the calibration impedance response, and whose sensing frequency on which the calibration impedance response was recorded is closest to the generated sensing frequency.

[0076] Calibration impedance responses may include calibration impedance responses acquired at different values ​​of the liquid's properties and at a single sensing frequency. However, it may not be sufficient for the set of calibration impedance responses to include calibration impedance responses of a variable characteristic at a single sensing frequency. For example, when sensing the response impedance of a curable two-component adhesive at a given sensing frequency and a given temperature of the adhesive within the sensing zone, a combination of a first mixing ratio and a first degree of curing may yield the same response impedance as a combination of a second mixing ratio and a second degree of curing. When attempting to derive a value for the characteristic "mixing ratio," this potential ambiguity can often be resolved by performing calibration measurements at various different sensing frequencies, since the mixing ratio and degree of curing often vary differently with the sensing frequency. Therefore, it may be advantageous to include data points of impedance responses at different mixing ratios at different sensing frequencies and different degrees of curing in the set of calibration impedance responses. Thus, in general, calibration impedance responses may include calibration impedance responses acquired at different values ​​of the liquid's properties and at two or more sensing frequencies.

[0077] The characteristic sensor of a sensor-equipped mixer described herein may be used to determine the mixing ratio of components of a two-component liquid, such as a two-component adhesive. The channel of the characteristic sensor is connected to the output of the mixer, thereby allowing the mixed liquid to flow through the channel. A dual-cartridge dispenser may be used to dispense the two components into the mixer, providing any mixing ratio of the components. In such a dispenser, two motors with microprocessor-controlled rotational speeds move two pistons into a cartridge (e.g., a standard two-component 4:1 cartridge such as the Sulzer MIXPATCH F-System). The motor speed may be controlled by pulse width modulation. To extend the motor speed range, the voltage supply to each motor is adjustable. For various mixing ratios, the first motor rotates at a given speed, and the speed of the second motor follows a coefficient based on the desired mixing ratio. The rotational speed and absolute linear position of the pistons define the volume of each component dispensed. The characteristic sensor may be located at the output end of the mixer, where it can sense the mixing ratio. The motor can be controlled to maintain or achieve a desired mixing ratio in a two-component liquid using the sensed value of the characteristic "mixing ratio".

[0078] The motors driving each piston can be monitored by monitoring the motor rotation speed using feedback from the motor actuators. The feedback loop uses information from the motor control system and does not require additional sensors. The motors can be monitored through rolling averages while they are operating. If the motor speed falls below a set threshold, the system can determine that an obstruction is likely present. This obstruction could be caused by a plunger in the cartridge during dispenser setup, or by something obstructing the free flow of liquid through the system during dispensing.

[0079] The dispenser can be improved by using a third motor to drive a conveyor pump between the cartridge and the mixer. To release cartridge pressure, such a conveyor pump can pump the components through the mixer from a common output nozzle of the two cartridges. This allows for much better and more accurate conveyance, especially for high-viscosity liquids with different mixing ratios.

[0080] In certain embodiments, the electrodes form a capacitor. The electrodes may be opposing parallel plates, such as opposing parallel square plates with sides of 13 mm spaced about 1 mm apart. Generally, the distance between electrodes can be at least 0.2 mm. The more viscous the liquid, the greater the distance between electrodes is generally required to avoid obstructing the flow. Preferably, the distance between electrodes is 1.0 mm to 10.0 mm. Depending on the required throughput and the type of liquid, the distance between electrodes may be, for example, 0.5 mm or more, 2.0 mm or more, 5.0 mm or more, 8.0 mm or more, 15.0 mm or more, or even several centimeters.

[0081] During use, the dielectric of the capacitor contains a liquid that flows through the sensing zone. When the sensing zone is filled with air and does not contain liquid, the capacitor may have a capacitance of 1 to 10 picofarads. Capacitors of such capacitance achieve a good signal-to-noise ratio in characteristic sensors such as those described herein.

[0082] Aging is known to alter the electrical properties of certain liquids. Aging can cause water loss from a liquid, which may result in a decrease in the number of polar molecules. Aging can also cause chemically unstable liquids to form new molecules. These changes over time may be detectable using characteristic sensors as described herein. Similarly, the open time of an adhesive can be considered a form of short-term aging and can be determined using a characteristic sensor in a sensor-equipped mixer according to this disclosure.

[0083] In certain embodiments, the liquid property is the liquid's age. A property sensor can derive a value for the liquid's age. As is known in chemistry and process engineering, the aging of a liquid refers to the change in the liquid's properties that occurs over time under normal storage conditions. Therefore, the "age" of a liquid refers to the state of the liquid acquired under normal storage conditions over the period since it first contained all of its components.

[0084] The pre-stored set of calibration data representing the calibration impedance response is recorded for a liquid that is not identical to the liquid used in the actual measurement, which can result in a significant discrepancy between the calibration impedance response and the actually measured response impedance. Therefore, characteristic sensors can also be used, for example, to detect when a liquid significantly different from the intended liquid, or a liquid with significantly different characteristics, passes through the characteristic sensor.

[0085] In a particular embodiment of the sensor-equipped mixer according to this disclosure, the characteristic sensor comprises a duct piece having a channel and an electrode. The duct piece comprises an inlet for liquid and an outlet for liquid, facilitating the flow of liquid from the inlet to the outlet. The inlet can be connected, for example, to the output end of a pipe that guides liquid, so that the liquid flows from the pipe into the duct piece. The pipe may be, for example, an output pipe of a mixer or an output hose of an extruder.

[0086] The inlet may have an inlet open section through which liquid can enter the duct piece. The outlet may have an outlet open section through which liquid can exit the duct piece. The size of the inlet open section and the size of the outlet open section may be equal. Alternatively, the size of the inlet open section may be larger than the size of the outlet open section. As a result, the liquid flow at the outlet of the duct piece will be faster than the flow at the inlet, which may be desirable in certain cases. Alternatively, the size of the inlet open section may be smaller than the size of the outlet open section. As a result, the liquid flow at the outlet of the duct piece will be slower than the flow at the inlet, which may be desirable in certain other cases.

[0087] For example, a channel within a duct piece may include a widened section through which liquid can flow. The widened section has an enlarged open section, and the size of this enlarged open section is larger than the size of the open section of the channel located upstream of the widened section. A larger cross-section can help reduce the liquid pressure within the widened section of the channel, thereby reducing the risk of mechanical deformation of the channel. Additionally, a wider open section can help reduce the flow velocity of the liquid within the widened section of the channel.

[0088] A channel may have a single available channel or multiple parallel available channels. Parallel channels allow liquid to flow through different subchannels. For example, the open cross-section of a channel in a widened section may be the sum of all open cross-sections of all available channels in the channel at a given location along the flow direction.

[0089] The sensing zone may be included in the widened portion, or the widened portion may form the sensing zone. Pressure reduction and flow velocity reduction within the sensing zone may help improve the accuracy of the characteristic sensor and reduce the risk of mechanical deformation of the electrodes.

[0090] Therefore, generally, in certain embodiments, the channel comprises a first longitudinal portion having a first open cross-section available for liquid flow, and a second longitudinal portion located downstream of the first longitudinal portion and having a second open cross-section available for liquid flow, wherein the second open cross-section is larger than the first open cross-section, and the sensing zone is included in the second longitudinal portion.

[0091] Generally, a duct piece can define several different parallel flow paths for the flow of liquid from inlet to outlet. One of these flow paths is the one that passes through the sensing zone. The other flow paths are sometimes called bypasses because the liquid flowing through them bypasses the sensing zone.

[0092] In certain embodiments, the channel is shaped so that all of the liquid entering the duct piece through the inlet flows through the sensing zone. This configuration may be beneficial because it allows for the sensing of characteristics for the entire volume of liquid within the channel's sensing zone, potentially resulting in a stronger response impedance signal.

[0093] However, in other embodiments, the duct piece is shaped such that a first portion of the liquid entering the duct piece through the inlet flows through a sensing zone to the outlet, and a second portion of the liquid entering the duct piece through the inlet flows through one or more bypasses to the outlet. Therefore, in certain embodiments, the channel includes a bypass, the bypass being arranged such that a first portion of the liquid flows through the sensing zone and a second portion of the liquid flows through the bypass that bypasses the sensing zone.

[0094] In certain embodiments, one of the electrodes is positioned between the sensing zone and the bypass. In certain embodiments, where the channel includes two or more bypasses, one of the electrodes is positioned between the sensing zone and the bypass. In other words, the bypass and the sensing zone may be positioned on either side of one of the electrodes. Such an arrangement can help improve the mechanical stability of the characteristic sensor because the same pressure in the liquid is exerted on both sides of the electrode, which can help avoid deformation of the electrode. Without such an arrangement, deformation would lead to fluctuations in the capacitance of the capacitor formed by the electrode, and, accordingly, uncontrolled fluctuations in the measured response impedance. These fluctuations may also depend on the liquid flow velocity.

[0095] In general, both electrodes can benefit from the pressure on both sides, especially if the electrodes are flat conductive areas on the surface of their respective printed circuit boards. Thus, in some embodiments, the duct piece is shaped such that a first portion of the liquid entering the duct piece through the inlet flows through a sensing zone to the outlet, a second portion of the liquid entering the duct piece through the inlet flows through a first bypass to the outlet, and a third portion of the liquid entering the duct piece through the inlet flows through a second bypass to the outlet. The sensing zone may be located between the electrodes. The first bypass and sensing zone may be located on both sides of the first electrode of the two electrodes, and the second bypass and sensing zone may be located on both sides of the second electrode of the two electrodes.

[0096] A characteristic sensor in a sensor-equipped mixer as described herein may comprise a second sensing zone located in a bypass through which the liquid flows during use, and two bypass electrodes for generating an electric field of one or more sensing frequencies within the second sensing zone. A characteristic value derivator may be electrically connected to the bypass electrodes and be operable to repeatedly i) generate an electric field of one or more sensing frequencies within the second sensing zone between the bypass electrodes while the liquid flows through the second sensing zone, ii) sense a second response impedance between the bypass electrodes at one or more sensing frequencies while the liquid flows through the second sensing zone and while the electric field is present, and iii) derive a characteristic value of the liquid's characteristics from the response impedance sensed in the (first) sensing zone and the second response impedance sensed in the second sensing zone, using a set of pre-stored calibration data representing a calibration impedance response.

[0097] A characteristic sensor having a first sensing zone and a second sensing zone within a bypass may allow for a greater flow rate of liquid through the sensor and / or a lower pressure in the channel, and may provide a stronger response impedance signal and a higher signal-to-noise ratio.

[0098] The characteristic sensor in a sensor-equipped mixer according to this disclosure may further comprise a temperature sensor for sensing the temperature of the liquid in the channel or the sensing zone. The response impedance may be highly dependent on the liquid temperature, and therefore, knowing the temperature of the liquid in the channel, and especially the liquid in the sensing zone, allows for improved accuracy in deriving the liquid characteristic values ​​from the response impedance using a pre-stored set of calibration data representing the calibration impedance response. It is desirable that the temperature of the liquid in the sensing zone be known with an accuracy of about 0.2°C.

[0099] The temperature sensor may be placed inside the duct piece. The temperature sensor may be positioned so that two opposing outer surfaces of the temperature sensor are in surface contact with the liquid. This configuration may help improve the accuracy of temperature sensing.

[0100] The characteristic sensor in a sensor-equipped mixer according to this disclosure may further comprise a velocity sensor for sensing the flow rate of a liquid through a channel or sensing zone. The velocity sensor may be useful in identifying partial or complete obstruction in the channel or other device through which the liquid flows before dispensing. If the liquid is a curable composition, the velocity sensor may help determine the time elapsed since curing began, thereby helping to estimate the curing state or degree of curing of the curable composition.

[0101] In certain embodiments, the flow sensor comprises an upstream temperature sensor and a downstream temperature sensor, as well as a heating resistor positioned close to the downstream temperature sensor. The current applied to the heating resistor heats the surrounding liquid. The liquid flow rate can be derived in a known manner from the temperature difference of the liquid determined between the temperature sensors. The upstream and downstream temperature sensors are in good thermal contact with the liquid. These sensors may be located, for example, within a duct piece, for example, within the housing of the duct piece. If the characteristic sensor comprises a duct piece, the flow sensor may be located within the duct piece.

[0102] To removably connect the duct piece to the existing mounting bayonet of the dual cartridge dispenser described above, the fastening device is slid over the inlet of the duct piece before the duct piece is mounted to the dispenser, and then rotated to mount the duct piece to the dispenser. The fastening device is equipped with a bayonet nut having an integrated hexagonal hole at the opposite end of the bayonet opening, in combination with the hexagonal end of the duct piece inlet.

[0103] After the duct piece is mounted on the cartridge, the bayonet nut can be rotated to secure the duct piece in place. During rotation of the nut, the flat area of ​​the hexagonal hole in the nut is positioned in front of the hexagonal edge of the duct piece. This prevents axial movement of the duct piece.

[0104] A characteristic sensor in a sensor-equipped mixer, as described herein, is connected to a mixing device to form a sensor-equipped mixer. This allows the characteristic sensor to determine the characteristic values ​​of the mixed liquid flowing out of the mixing device.

[0105] A mixing device is capable of mixing two or more components to produce a mixed liquid at the output of the mixing device. A characteristic sensor can, for example, determine the mixing ratio of the mixed liquid flowing out from the output of the mixing device. If the thus determined mixing ratio is outside a desired band of acceptable mixing ratios, the characteristic sensor generates a warning signal to prompt operator action or generates a control signal to change the relative input amount of components entering the mixing device.

[0106] Accordingly, the present disclosure provides a sensor-equipped mixer comprising a mixing device for mixing two or more components to produce a mixed liquid in a mixer output section, and a characteristic sensor, as described herein, which is in fluid communication with the mixer output section so that the mixed liquid can flow from the mixer output section through a sensing zone.

[0107] In a further aspect, the disclosure also relates to a process for determining characteristic values ​​of the properties of a liquid, i) Providing a liquid and a characteristic sensor as described herein, and allowing the liquid to flow through a sensing zone, ii) The step of generating an electric field of one or more sensing frequencies within the sensing zone between electrodes while the liquid flows through the sensing zone, iii) While the liquid is flowing through the sensing zone and while an electric field is present, the step of sensing the response impedance between electrodes at one or more sensing frequencies, iv) A step of deriving characteristic values ​​of the liquid's properties from the response impedance using a pre-stored set of calibration data representing the calibration impedance response, Provide a process that includes these in this order.

[0108] This determination process makes it possible to determine the properties of a liquid, such as the mixing ratio of a two-component adhesive, the curing state of a curable composition, or its aging state. Calibration impedance responses previously measured at one or more sensing frequencies and at various characteristic values ​​of the liquid's properties form a multidimensional data field specific to the liquid. This data field is represented by a set of calibration data. This allows the characteristic value derivator described above to determine the values ​​of the liquid's properties from the actually measured response impedance.

[0109] The characteristic sensor described above is operable to perform steps ii), iii), and iv) of the determination process.

[0110] In describing the characteristic sensor in a sensor-equipped mixer as described herein, several modifications that may be implemented to generate an electric field, sense response impedance, and derive characteristic values ​​are disclosed herein. These modifications can be similarly implemented for the determination process described in the previous paragraph and yield substantially the same benefits and advantages.

[0111] The first step i) of the determination process may be preceded by a calibration process, i.e., a preceding step of determining the calibration impedance response and pre-storing in a data storage device a set of calibration data representing the calibration impedance response measured in the same characteristic sensor using the same liquid. The same liquid has the same properties as the liquid later measured in the characteristic sensor to determine one of the values ​​of the properties. The same liquid is sometimes called the "calibration liquid" because it is used to generate the calibration impedance response and the calibration data representing the calibration impedance response.

[0112] This preceding step may include a substep of providing a characteristic sensor comprising m) a channel including a sensing zone through which the same liquid flows when in use, and two electrodes for generating an electric field of one or more sensing frequencies within the sensing zone; n) a substep of providing the same liquid having characteristics of known characteristic values; o) a substep of generating an electric field of one or more sensing frequencies between the electrodes within the sensing zone while the same liquid flows through the sensing zone; and p) a substep of sensing between the electrodes at one or more sensing frequencies while the same liquid flows through the sensing zone and while the electric field is present.

[0113] This preceding step can be repeated several times to generate a set of calibration data representing the calibration impedance response usable in the determination process described above, for multiple characteristic values ​​of the calibration fluid's properties.

[0114] In certain embodiments of the determination process, at least one of the one or more sensing frequencies is a frequency of 32 Hz, 100 Hz, 1000 Hz, 5000 Hz, or 8000 Hz. Generally, at least one of the one or more sensing frequencies may be in the range of 1 Hz to 10000 Hz (10 kHz). At least one of the one or more sensing frequencies may be in the range of 1 Hz to 100000 Hz (100 kHz). In certain preferred embodiments of the determination process, the sensing frequency is in the range of 200 Hz to 2000 Hz, because small differences in the values ​​of key properties of a particular industrial liquid result in particularly large differences in response impedance in this frequency range.

[0115] The voltage between the electrodes can be between 0.1 volts and 100 volts. Typically, this voltage is a few volts, for example, between 1 volt and 20 volts, preferably between 1 volt and 10 volts. In the case of a particular liquid and electrode configuration, the voltage between the electrodes may be as low as 0.1 volts, while in the case of other liquids and electrode configurations, the voltage between the electrodes may be 100 volts, or any voltage between 0.1 volts and 100 volts.

[0116] In certain embodiments, the amplitude of the electric field is between 100 volts / meter and 20,000 volts / meter. Such amplitudes at sensing frequencies within the aforementioned range have been found to facilitate reliable sensing of response impedance with sufficient accuracy while avoiding electrolysis or electrical discharge through the liquid.

[0117] Therefore, in some of these embodiments, at least one of the one or more sensing frequencies is in the range of 1 Hz to 10,000 Hz, and the amplitude of the electric field is in the range of 100 volts / meter to 20,000 volts / meter.

[0118] The determination process and characteristic sensor can be used to determine the characteristic values ​​of a wide range of liquids. In principle, almost all liquids that yield different response impedances at different characteristic values ​​can be used. In certain embodiments of the determination process, the liquid is an adhesive, a curable adhesive, a two-component adhesive, a multi-component adhesive, or a curable two-component adhesive. In certain embodiments, the liquid is a liquid adhesive. In some of these embodiments, the liquid is a curable liquid adhesive. In some of these embodiments, the liquid is a curable two-component liquid adhesive. "Two-component" means that the adhesive consists of a first component and a second component, which are mixed, for example, in a static or dynamic mixer to form the adhesive. Similarly, "multi-component" means that the adhesive consists of multiple components, e.g., two, three, four, or more components, which are mixed, for example, in a static or dynamic mixer to form the adhesive.

[0119] Liquids referred to herein in the context of characteristic sensors or determination processes may have a dynamic viscosity of 10 Pa.s (Pascal-seconds) to 40,000.0 Pa.s, measured at a temperature of 25°C. The term “viscous liquid” as used herein refers to liquids having a dynamic viscosity of 10 Pa.s to 40,000 Pa.s. Liquids with higher dynamic viscosities can only flow through the sensing zone of a characteristic sensor under excessive pressure, which risks damaging the sensor. Dynamic viscosity can be determined using a Stubinger viscometer according to ASTM D7042-12a.

[0120] Therefore, in certain embodiments of the characteristic sensor and determination process, the liquid has a dynamic viscosity of 10 Pascal seconds to 40,000.0 Pascal seconds, measured at 25°C according to the standard ASTM D7042-12a, version effective July 1, 2020.

[0121] The disclosure also provides a set of calibration data representing calibration impedance responses for use in the determination process described above, the set of calibration data further represents a characteristic value of the characteristic of the calibration liquid in which one characteristic value of the calibration impedance response is sensed.

[0122] A specific characteristic value of a liquid can only be determined if a set of calibration impedance responses has been recorded for multiple values ​​of that particular characteristic of the same liquid. Such a set of calibration impedance responses can be generated by performing a calibration of a liquid with known values ​​of the characteristic in the determination process and the characteristic sensor, recording the response impedance of the characteristic of the calibration liquid for this value, and repeating this process for several values ​​of the same characteristic of the calibration liquid. The resulting set of calibration impedance responses is stored on the characteristic sensor's data storage device before performing the actual liquid to be measured by the characteristic sensor or the determination process. The "priorly stored" part means "before" this.

[0123] The calibration liquid is the same liquid used later in the characteristic sensor or determination process to determine the characteristic value.

[0124] A set of calibration data representing the calibration impedance response can be pre-stored in a data storage device in any format. For example, it may be pre-stored in a format of n elements, where the elements of the n-element set are characteristic values ​​and the other elements of the n-element set are the calibration impedance responses determined in those characteristic values.

[0125] Characteristic values ​​may only be determinable by measurements at different sensing frequencies. In a specific scenario where two properties of a liquid, for example, the mixing ratio and degree of curing in a two-component curable liquid, vary over time, a 1:4 mixing ratio of the uncured liquid may produce the same response impedance at a specific sensing frequency as a 1:3 mixing ratio of the liquid after 5 minutes of curing. If a single sensing frequency is used, this ambiguity may not be resolved. However, when sensing response impedance at two different sensing frequencies, the response impedances may be different, which can help distinguish between the mixing ratios.

[0126] Therefore, sensing the response impedance at different sensing frequencies can help resolve ambiguities and derive characteristic values ​​with greater accuracy and reliability. To do this, a pre-stored set of calibration data representing the calibration impedance response must include datasets recorded for different sensing frequencies, each dataset containing the values ​​for the sensing frequency, for example, as n elements.

[0127] Therefore, in a particular embodiment of the set of calibration data representing the calibration impedance response, the set of calibration data may further represent the sensing frequency at which one of the calibration impedance responses is sensed.

[0128] The temperature of the liquid within the sensing zone typically significantly affects the measured response impedance. The calibration impedance response data points advantageously include the liquid temperature value within the sensing zone at the temperature at which the calibration impedance response was recorded. A pre-stored set of calibration data representing the calibration impedance response then needs to represent this temperature, facilitating the use of the calibration impedance response to derive characteristic values ​​of the liquid's properties from the sensed response impedance at similar temperatures.

[0129] Therefore, in a particular embodiment of the set of calibration data representing the calibration impedance response, the set of calibration data further represents the temperature of the liquid in the sensing zone in which one of the calibration impedance responses is sensed.

[0130] A particular set of calibration data combines representations of sensing frequency and temperature. In a particular embodiment of a set of calibration data representing a calibration impedance response, the set of calibration data further represents the sensing frequency at which one of the calibration impedance responses was sensed, and / or the set of calibration data further represents the temperature of the liquid in the sensing zone at which one of the calibration impedance responses was sensed.

[0131] The characteristic sensors and related processes described herein can be used in a variety of different applications, such as double-checking adhesive materials in secure design joints in the rail, automotive, or aerospace industries where critical components are installed, and documenting measurements. A second potential application is response-based purging. Automated systems for dispensing curable materials often operate in cycle times that include interruptions for readjustment, joining, and component replacement. During these interruptions, the material cures in the mixing nozzle and needs to be purged at a specific curing level. The sensor can sense the current curing state and initiate curing when needed, resulting in less waste and optimized cycle time. Further applications may be during dispensing. At the start and end of use of static mixer systems, deviations in mixing ratio and mixing quality often occur. The characteristic sensor can reveal these deviations and trigger adjustments to the dynamic parameters of the dispensing system, such as flow rate, preload, and timing. In this way, the expansion effect of hoses and reservoirs can also be reduced. Further applications include the processing of sample / material twins, where the sensor can be periodically checked to control the curing of adhesives or fillers during complex processes, according to all process conditions, such as materials on parts that are filled at specific process steps and then go through a curing furnace, painting environment, etc. The characteristic sensor and process in a sensor-equipped mixer according to this disclosure can also be used for shelf life indication. Materials with condition-based shelf life specifications can be tested by comparing sensor data with calibration data for materials stored under controlled conditions. [Brief explanation of the drawing]

[0132] Herein, aspects of the present invention will be described in more detail with reference to the following diagrams illustrating specific embodiments. [Figure 1] These are cross-sectional and circuit diagrams of the elements of the characteristic sensor in the sensor-equipped mixer according to this disclosure. [Figure 2] These are cross-sectional and circuit diagrams of the elements of the alternative characteristic sensor in the sensor-equipped mixer according to this disclosure. [Figure 3]This is a side view of the sensor-equipped mixer according to the present disclosure. [Figure 4] This is a perspective view of a duct piece including the channel and electrode of a characteristic sensor in a sensor-equipped mixer according to the present disclosure. [Figure 5] Figure 4 is a perspective cross-section of the duct piece.

[0133] Figure 1 shows some key elements of the characteristic sensor of the sensor-equipped mixer according to this disclosure, in a combination of a cross-sectional view and a circuit diagram. The liquid 10 flows through the channel 20. The first electrode 30 and the second electrode 40 are positioned opposite each other and can generate an electric field between the electrodes 30 and 40. The portion of the channel 20 within the electric field between electrodes 30 and 40 is a sensing zone 50 in which characteristic values ​​of the liquid 10 can be determined.

[0134] To generate an electric field between electrodes 30 and 40 within the sensing zone 50, electrodes 30 and 40 are electrically connected to a voltage source 60 that applies an alternating current (AC) voltage of one or more frequencies, which is the "sensing frequency," to electrodes 30 and 40, and as a result, the liquid 10 within the sensing zone 50 is exposed to the AC electric field.

[0135] An ammeter 70 is connected to electrodes 30 and 40 to measure the current passing through electrodes 30 and 40, thereby sensing the impedance between electrodes 30 and 40. This impedance is sensed in response to the electric field applied between electrodes 30 and 40 and is affected by the properties of the liquid 10 in the sensing zone 50; therefore, the impedance is also referred to herein as the "response impedance".

[0136] A useful sensing frequency range can be, for example, between 1 Hz and 10,000 Hz. In the configuration shown in Figure 1, a sensing frequency of 250 Hz is successfully used.

[0137] In the embodiment shown in Figure 1, electrodes 30 and 40 are opposing, flat, parallel square plates with sides 13 mm long, spaced approximately 1 mm apart from each other, forming a plate capacitor. The capacitance of the resulting plate capacitor in air is approximately 2 picofarads (pF).

[0138] The planar capacitor configuration of electrodes 30 and 40 in the embodiment of Figure 1 generates a homogeneous electric field between the plates, but other electric field geometries may be useful, for example, the configuration illustrated in Figure 2 shows elements of an alternative characteristic sensor in a sensored mixer according to this disclosure. In this embodiment, the planar electrodes 30 and 40 are located on the same side of the channel 20. By arranging electrodes 30 and 40 side by side on the same side of the channel 20, a highly heterogeneous electric field is generated. Specific lines of force of the electric field in the fringed electric field extend through the sensing zone 50 so that the electric field can be used to sense the characteristics of the liquid 10 within the sensing zone 50.

[0139] Figure 3 is a side view of a sensor-equipped mixer according to the present disclosure, attached to a dispenser and mixer for a viscous two-component adhesive. The first component A and the second component B of the adhesive are extruded from their respective cartridges 100 and 110 and pass through the static mixer 120. At the output section 170 of the static mixer, the mixed adhesive passes through the characteristic sensor 1 before being dispensed at the output section of the duct piece of the characteristic sensor 1. The characteristic sensor 1 senses the mixing ratio of component A and component B in the mixed adhesive.

[0140] Cartridges 100 and 110 contain viscous components A and B, respectively. Each piston 130 moves further into cartridges 100 and 110, pushing out components A and B. Pistons 130 are driven by independently controllable motors 140 and 150, and the pressure generated by pistons 130 moves the unmixed components and the mixed viscous adhesive 10 after mixing through the static mixer 120 and the channel 20 of the characteristic sensor 1. Motors 140 and 150 are connected to the characteristic sensor 1 to establish a feedback loop. When the characteristic sensor 1 senses a mixing ratio outside the acceptable band of the desired mixing ratio, motors 140 and 150 can be individually controlled to push more component A and / or less component B (or vice versa) into the static mixer 120 to adjust the mixing ratio toward the desired mixing ratio. Both motors 140 and 150 can be controlled separately to obtain the desired total throughput per second of the mixed adhesive to be dispensed.

[0141] The static mixer 120 receives the unmixed components A and B of the two-component adhesive at its input terminal 160. The lamellae within the static mixer 120 repeatedly redirect the flow of the input material, introducing shear forces that help mix components A and B together. The output terminal 170 of the static mixer 120 is connected to the inlet 180 of a duct piece 200 (shown in the longitudinal section view), which contains the channel 20, sensing zone 50, and electrodes 30 and 40 of the characteristic sensor 1, as described in the context of Figures 1 and 2. Thus, the mixed adhesive 10 can exit the static mixer 120 and enter the duct piece 200. The duct piece 200 is described in more detail in Figure 4. At the outlet 190 of the duct piece 200, the mixed adhesive 10 is dispensed.

[0142] Electrodes 30 and 40 are flat, parallel plates facing each other. These electrodes are connected via wire 210 to a computerized control system 220, which supplies a 6-volt AC voltage to electrodes 30 and 40 to generate an electric field within the sensing zone 50 at a sensing frequency of 250 Hz. The control system also measures the current flowing through electrodes 30 and 40 and, taking into account the current, voltage, and sensing frequency, senses the response impedance between electrodes 30 and 40.

[0143] The computerized control system 220 has an internal data storage device 230, i.e., a hard disk 230, which stores a set of calibration data representing the calibration impedance response. These calibration impedance responses are recorded in advance, i.e., before measurement, during a calibration process in which the same mixed viscous adhesive 10 is produced as a result of using the same duct piece 200 and the same components A and B. During the calibration process, the mixing ratio A / B is adjusted to a specific fixed calibration mixing ratio (CMR), and for each of these calibration mixing ratios, the calibration impedance response (CIR) is sensed at five different calibration sensing frequencies (CSF). These datasets are recorded on the hard disk 230 in the form of a triplicate, for example, (CMR, CSF, CIR). These datasets form a three-dimensional data field specific to the viscous adhesive. The datasets are used to construct a parameterized multidimensional model of the datasets based on a multidimensional polynomial. This parameterized model facilitates rapid computer interpolation between individual datasets and the rapid derivation of characteristic values ​​of the liquid's properties in subsequent measurements. The parameters of the parameterized model form a set of calibration data representing the datasets recorded during the calibration process.

[0144] Subsequently, when the characteristic "mixing ratio" value of the viscosity of the two-component adhesive of components A and B is actually measured in the characteristic sensor 1, the measured impedance response (MIR) is measured at a specific measurement sensing frequency (MSF) and recorded in the control system 220. To derive the mixing ratio value from the measured impedance response at the measurement sensing frequency, the software running on the control system 220 identifies a set of calibration impedance response triplets that has the closest calibration response impedance to the measured impedance response and the closest calibration sensing frequency to the measurement sensing frequency. This identification and potential interpolation can be easily performed by using a parameterized multidimensional polynomial that models multiple triplets of multiple datasets, i.e., (CMR, CSF, CIR). From these calibration data, the software derives the (previously unknown) mixing ratio value in the actual measurement.

[0145] The same sensing frequency used for calibration is often used for measurement. However, a mixing ratio may occur in measurement where the calibration impedance response is not determined in calibration. Therefore, both the sensing frequency and response impedance may not exactly match between triplets in the calibration dataset. In such cases, interpolation between two suitably selected calibration triplets, each containing two calibration impedance responses close to the measured response impedance, results in an interpolated calibration mixing ratio, which can then be considered the mixing ratio in measurement. The interpolation is performed by software on the control system 220 using a parameterized multidimensional polynomial.

[0146] The interpolation and derivation result is the value of the mixing ratio of component A to component B in the mixed two-component adhesive 10 in the sensing zone 50 during measurement.

[0147] In this embodiment, the calibration impedance response was measured depending on two parameters, namely the sensing frequency and the mixing ratio. In other embodiments, dependence of the impedance response on further parameters, such as the temperature of the adhesive within the sensing zone, may be considered. The dataset of the calibration impedance response is then a set of four values, such as (CMR, CSF, CIR, temperature), and the pre-stored set of calibration impedance responses is a set of fours that form a four-dimensional data field specific to viscous adhesives. By taking further parameters into account, the dataset can be a set of five values ​​or a higher set of values, and as a result, the dataset of the calibration impedance response is a larger-dimensional multidimensional data field that can be represented by different parameterized multidimensional polynomials.

[0148] The control system 220 records the mixing ratio value along with a timestamp for quality assurance. In the particular embodiment shown in Figure 3, the motors 140 and 150 that push components A and B, respectively, into the static mixer 120 are connected to and controlled by the control system 220. The mixing ratio derived during actual measurement is continuously checked against a desired mixing ratio. If the deviation from the desired mixing ratio is greater than acceptable, the control system 220 adjusts the measured mixing ratio toward the desired mixing ratio by suitably changing the speed of one or both of the motors 140 and 150.

[0149] Figure 4 is a perspective view of the duct piece 200 of the characteristic sensor 1 in Figure 3. The housing 330 of the duct piece 200 forms an inlet 180 and an outlet 190, the inlet 180 being connected to the output terminal 170 of the static mixer 120. The viscous adhesive 10 is dispensed through the outlet 190. Thus, the duct piece 200 forms a channel 20 for the viscous adhesive 10 to flow from the inlet 180 to the outlet 190. During operation, the duct piece 200 is completely filled with the mixed viscous adhesive 10.

[0150] As indicated by the shape of the housing 330, the duct piece 200 includes a widened intermediate section 260. The channel 20 is wider in the intermediate section 260 of the duct piece 200 than in the inlet 180, and as a result, the intermediate section 260 has a larger open cross-section available for the adhesive 10 to flow through. The size of the widened open cross-section of the intermediate section 260 is larger than the size of the open cross-section of the inlet 180. This reduces the pressure and flow velocity of the adhesive 10 in the intermediate section 260 of the duct piece 200, and consequently facilitates accurate sensing of the response impedance in the duct piece 200.

[0151] In this embodiment, electrodes 30 and 40 are formed by conductive layers on two separate printed circuit boards (PCBs) 240 and 250, which extend laterally through a duct piece 200 and project onto the side surface of the duct piece 200. The first electrode 30 is a conductive layer on the underside of the first upper PCB 240. The first electrode faces the second electrode 40, which is a further conductive layer on the upper surface of the second lower PCB 250. Thus, electrodes 30 and 40 are parallel conductive plates separated by a gap through which a portion of the adhesive 10 flows from an inlet 180 to an outlet 190.

[0152] Keeping the extended portions of electrodes 30 and 40 short in the direction of the flow path 270 is generally advantageous because it reduces the flow resistance and pressure of the liquid 10 on electrodes 30 and 40.

[0153] Figure 5 is a perspective cross-section of the duct piece 200 shown in Figure 4. Through the output terminal 170 of the static mixer, the liquid adhesive 10 is transported through the channel 20 and then through the duct piece 200 and dispensed through the outlet 190.

[0154] The upper PCB 240 and lower PCB 250 are positioned parallel to each other and parallel to the flow direction of the liquid adhesive 10 in the channel 20 between the inlet 180 and the outlet 190. Each PCB 240, 250 has a flat conductive patch on the surface facing the other PCB 240, 250 that forms the electrodes 30, 40 of the characteristic sensor 1. In Figure 5, only the electrode 40 on the upper surface of the lower PCB 250 is visible, while the opposing electrode 30 on the lower surface of the upper PCB 240 is not visible. As described above, an electric field is generated between electrodes 30 and 40. Electrodes 30, 40 are embedded in the flow of the liquid adhesive 10 and are in contact with the liquid adhesive 10. Electrodes 30, 40 can be electrically connected via conductive traces (not shown) on the surfaces of each PCB 240, 250 that extend through the walls of the housing 330 to the outside of the housing 330.

[0155] The sensing zone 50 is a portion of the channel 20 between electrodes 30 and 40. The first portion 270 of the liquid adhesive 10 flows through the sensing zone 50 between electrodes 30 and 40 and is used to sense the response impedance between electrodes 30 and 40. In the embodiment shown in Figure 5, the duct piece 200 defines three different parallel n-flow channels for the flow of the liquid adhesive 10 from the inlet 180 to the outlet 190. The first flow channel 270 passes through the sensing zone 50 between electrodes 30 and 40. The second flow channel for the second portion 280 of the adhesive 10 passes through the upper bypass 290 between the upper surface of the upper PCB 240 and the upper wall 320 of the housing 330 of the duct piece 200, and the third flow channel for the third portion 300 of the adhesive 10 passes through the lower bypass 310 between the lower surface of the lower PCB 250 and the lower wall 340 of the housing 330. All three channels, including bypasses 290 and 310, are part of channel 20 through which the adhesive 10 flows from inlet 180 to outlet 190.

[0156] Each of the bypasses 290 and 310 has an open cross-section for the flow of liquid adhesive 10, which is approximately equal to the open cross-section of the flow path through the sensing zone 50 between electrodes 30 and 40. Therefore, the pressure difference between the upper and lower surfaces of PCBs 240 and 250 is small, which helps to reduce, or even avoid, the deformation of PCBs 240 and 250 and the associated errors in response impedance sensing.

[0157] The duct piece 200 includes a temperature sensor 350 positioned in the center of the channel 20 before the channel 20 divides into different flow paths 50, 290, and 310. The temperature sensor 350 senses the temperature of the adhesive 10 before a portion 270 of the adhesive 10 enters the sensing zone 50. Since several response impedances and calibration impedance responses measured to derive values ​​for specific properties of the adhesive 10 vary considerably with the temperature of the adhesive 10, it is important to measure the temperature with high accuracy, e.g., ±0.1°C. However, in a specific property sensor 1 where it can be guaranteed that the adhesive 10 entering the duct piece 200 has a distinct temperature, the temperature sensor may not be necessary.

[0158] The duct piece 200 also includes a flow sensor 360 for determining the flow rate of adhesive 10 through the channel 20. If the adhesive 10 changes its properties in the short time it moves through the mixer 120 into the channel 20, the flow sensor 360 can determine the approximate time the adhesive flows through the mixer 120 into the duct piece 200, thereby estimating an approximate value of its properties. The flow sensor 360 can also help detect interruptions in the dispensing of adhesive 10 in the duct piece 200 and associated curing, which could render certain measurement results meaningless. The flow sensor 360 is located downstream from the sensing zone 50 and includes a heating resistor 370 and a second temperature sensor 380 located near the heating resistor 370. A suitable current applied to the heating resistor 370 heats the surrounding adhesive 10, and the flow rate can be derived from the temperature difference between the first temperature sensor 350 and the second temperature sensor 380 upstream of the sensing zone 50. In addition to each embodiment, the following embodiments are also described. (Note 1) A sensor-equipped mixer having a mixing device (120) for mixing two or more components (A, B) to produce a mixed liquid (10) at a mixer output unit (170), and a characteristic sensor (1) for determining characteristic values ​​of the characteristics of the liquid (10), The characteristic sensor is a) A channel (20) including a sensing zone (50) through which the liquid flows when in use, b) Two electrodes (30, 40) for generating an electric field of one or more sensing frequencies within the sensing zone, c) A data storage device (230) including a pre-stored set of calibration data representing calibration impedance responses previously measured at one or more sensing frequencies and at various characteristic values ​​of the same liquid's properties, d) A characteristic value derivator (220) electrically connected to the electrodes (30, 40), which repeatedly i) While the liquid (10) flows through the sensing zone (50), an electric field of one or more sensing frequencies is generated between the electrodes (30, 40) within the sensing zone. ii) While the liquid (10) flows through the sensing zone (50) and while the electric field is present, the response impedance between the electrodes (30, 40) is sensed at one or more sensing frequencies. iii) Using the pre-stored set of calibration data representing the calibration impedance response, the characteristic values ​​of the liquid (10) are derived from the response impedance. A characteristic value derivator that can operate in such a manner, A sensor-equipped mixer, wherein the characteristic sensor (1) is in fluid communication with the mixer output section (170) so that the mixed liquid (10) can flow from the mixer output section (170) through the sensing zone (50). (Note 2) The channel (20) has a first longitudinal portion (180) having a first open cross-section available for the flow of the liquid (10), A second longitudinal portion (260) is located downstream of the first longitudinal portion (180) and has a second open cross-section available for the flow of the liquid, Equipped with, The sensor-equipped mixer according to Appendix 1, wherein the second open cross section is larger than the first open cross section, and the sensing zone (50) is included in the second longitudinal portion (260). (Note 3) A sensor-equipped mixer according to Appendix 1 or 2, wherein one or both of the electrodes (30, 40) are arranged to come into contact with the liquid (10) as the liquid flows through the sensing zone (50). (Note 4) The sensing zone (50) is located between the electrodes (30, 40) and is a sensor-equipped mixer as described in any one of the appendices 1 to 3. (Note 5) A sensor-equipped mixer according to any one of the appendices 1 to 4, wherein the channel (20) includes bypasses (290, 310), the bypasses being arranged such that a first portion (270) of the liquid (10) flows through the sensing zone (50) and a second portion (280, 300) of the liquid flows through the bypasses (290, 310) that bypass the sensing zone. (Note 6) A sensor-equipped mixer as described in Appendix 5, wherein one of the electrodes (30, 40) is positioned between the sensing zone (50) and the bypass (290, 310). (Note 7) A sensor-equipped mixer according to any one of the appendices 1 to 6, further comprising a temperature sensor (350) for sensing the temperature of the liquid (10) in the channel (20) or the sensing zone (50). (Note 8) A sensor-equipped mixer according to any one of the appendices 1 to 7, further comprising a flow velocity sensor (360) for sensing the flow velocity of the liquid (10) passing through the channel (20) or the sensing zone (50). (Note 9) A process for determining the characteristic values ​​of the properties of a liquid (10), i) A liquid (10) and a characteristic sensor (1) for determining the characteristic values ​​of the properties of the liquid (10), The characteristic sensor is a) A channel (20) including a sensing zone (50) through which the liquid flows when in use, b) Two electrodes (30, 40) for generating an electric field of one or more sensing frequencies within the sensing zone, c) A data storage device (230) including a pre-stored set of calibration data representing calibration impedance responses previously measured at one or more sensing frequencies and at various characteristic values ​​of the same liquid's properties, d) A characteristic value derivator (220) electrically connected to the electrodes (30, 40), which repeatedly 1) While the liquid (10) flows through the sensing zone (50), an electric field of one or more sensing frequencies is generated within the sensing zone between the electrodes (30, 40), 2) While the liquid (10) flows through the sensing zone (50) and while the electric field is present, the response impedance is sensed between the electrodes (30, 40) at one or more sensing frequencies. 3) Using the pre-stored set of calibration data representing the calibration impedance response, the characteristic values ​​of the liquid (10) are derived from the response impedance, and the liquid (10) is made to flow through the sensing zone (50). A characteristic sensor (1) comprises a characteristic value derivator that is capable of operating in such a manner, To provide, ii) While the liquid (10) flows through the sensing zone (50), an electric field of one or more sensing frequencies is generated between the electrodes (30, 40) within the sensing zone (50), iii) While the liquid (10) flows through the sensing zone (50) and while the electric field is present, the response impedance between the electrodes (30, 40) is sensed at one or more sensing frequencies, iv) Using the pre-stored set of calibration data representing the calibration impedance response, derive characteristic values ​​of the liquid (10) from the response impedance, A process that includes these elements in this order. (Note 10) The method according to Appendix 9, wherein at least one of the one or more sensing frequencies is in the range of 1 Hz to 10,000 Hz, and the amplitude of the electric field is in the range of 100 volts / meter to 20,000 volts / meter. (Note 11) The method according to Appendix 9 or 10, wherein the liquid (10) is an adhesive, a curable adhesive, a two-component adhesive, a multi-component adhesive, or a curable two-component adhesive. (Note 12) The method according to any one of the appendices 9 to 11, wherein the liquid (10) has a dynamic viscosity of 10 pascal seconds to 40,000.0 pascal seconds, as measured at 25°C in accordance with the version of the standard ASTM D7042-12a effective July 1, 2020. (Note 13) A set of calibration data representing calibration impedance responses for use in the process described in Appendix 9, wherein one of the calibration impedance responses further represents a characteristic value of the characteristic of the calibration liquid that was sensed. (Note 14) A set of calibration data representing the calibration impedance response as described in Appendix 13, wherein the set of calibration data further represents a sensing frequency at which one of the calibration impedance responses is sensed, and / or the set of calibration data further represents the temperature of the liquid (10) in the sensing zone (50) at which one of the calibration impedance responses is sensed.

Claims

1. A sensor-equipped mixer comprising a mixing device for mixing two or more components to produce a mixed liquid at the mixer output section, and a characteristic sensor for determining characteristic values ​​of the characteristics of the mixed liquid, The characteristic sensor is A channel including a sensing zone through which the mixed liquid flows during use, Two electrodes for generating an electric field of one or more sensing frequencies within the sensing zone, A data storage device including a pre-stored set of calibration data representing calibration impedance responses previously measured at one or more sensing frequencies and at various characteristic values ​​of the same liquid's properties, A characteristic value derivator electrically connected to the electrode, which repeatedly While the mixed liquid flows through the sensing zone, an electric field of one or more sensing frequencies is generated between the electrodes within the sensing zone. While the mixed liquid flows through the sensing zone and while the electric field is present, the response impedance is sensed between the electrodes at one or more sensing frequencies. Using the pre-stored set of calibration data representing the calibration impedance response, the characteristic values ​​of the properties of the mixed liquid are derived from the response impedance. A characteristic value derivator that can operate in such a manner, A sensor-equipped mixer, wherein the characteristic sensor is in fluid communication with the mixer output section so that the mixed liquid can flow from the mixer output section through the sensing zone.

2. The channel has a first longitudinal portion having a first open cross-section available for the flow of the mixed liquid, A second longitudinal portion located downstream of the first longitudinal portion and having a second open cross-section available for the flow of the mixed liquid, Equipped with, The sensor-equipped mixer according to claim 1, wherein the second open cross section is larger than the first open cross section, and the sensing zone is included in the second longitudinal portion.

3. A sensor-equipped mixer according to claim 1 or 2, wherein one or both of the electrodes are arranged to come into contact with the mixed liquid as the mixed liquid flows through the sensing zone.

4. The sensor-equipped mixer according to any one of claims 1 to 3, wherein the sensing zone is located between the electrodes.

5. A sensor-equipped mixer according to any one of claims 1 to 4, wherein the channel includes a bypass, the bypass being arranged such that a first portion of the mixed liquid flows through the sensing zone and a second portion of the mixed liquid flows through the bypass, bypassing the sensing zone.

6. The sensor-equipped mixer according to claim 5, wherein one of the electrodes is positioned between the sensing zone and the bypass.

7. A sensor-equipped mixer according to any one of claims 1 to 6, further comprising a temperature sensor for sensing the temperature of the mixed liquid in the channel or the sensing zone.

8. A sensor-equipped mixer according to any one of claims 1 to 7, further comprising a flow velocity sensor for sensing the flow velocity of the mixed liquid passing through the channel or the sensing zone.

9. A method for determining the characteristic values ​​of the properties of a mixed liquid, A mixing device mixes two or more liquids to produce a mixed liquid, A characteristic sensor for determining the characteristic value of the properties of the mixed liquid, The characteristic sensor is A channel including a sensing zone through which the mixed liquid flows during use, Two electrodes for generating an electric field of one or more sensing frequencies within the sensing zone, A data storage device including a pre-stored set of calibration data representing calibration impedance responses previously measured at one or more sensing frequencies and at various characteristic values ​​of the same liquid's properties, A characteristic value derivator electrically connected to the electrode, which repeatedly While the mixed liquid flows through the sensing zone, an electric field of one or more sensing frequencies is generated between the electrodes within the sensing zone. While the mixed liquid flows through the sensing zone and while the electric field is present, the response impedance is sensed between the electrodes at one or more sensing frequencies. Using the pre-stored set of calibration data representing the calibration impedance response, the characteristic values ​​of the mixed liquid are derived from the response impedance, and the mixed liquid is allowed to flow through the sensing zone. To provide a characteristic sensor comprising a characteristic value derivator that can operate in such a manner, While the mixed liquid flows through the sensing zone, an electric field of one or more sensing frequencies is generated between the electrodes within the sensing zone. While the mixed liquid flows through the sensing zone and while the electric field is present, the response impedance between the electrodes is sensed at one or more sensing frequencies. Using the pre-stored set of calibration data representing the calibration impedance response, the characteristic values ​​of the properties of the mixed liquid are derived from the response impedance. A method that includes these in this order.

10. The method according to claim 9, wherein at least one of the one or more sensing frequencies is a frequency between 1 Hz and 10,000 Hz, and the amplitude of the electric field is between 100 volts / meter and 20,000 volts / meter.

11. The method according to claim 9 or 10, wherein the mixed liquid is an adhesive, a curable adhesive, a two-component adhesive, a multi-component adhesive, or a curable two-component adhesive.

12. The method according to any one of claims 9 to 11, wherein the mixed liquid has a dynamic viscosity of 10 Pascal seconds to 40,000.0 Pascal seconds, as measured at 25°C according to the version of the standard ASTM D7042-12a effective July 1, 2020.

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