Online turbidity-based solubility and solids content measurement device, system, and method

Abstract

The application discloses a solubility and solid content measuring device, system and method based on online turbidity, the measuring device comprises a stirrer, a container for containing a to-be-measured substance and a coupled measuring device configured to simultaneously measure the turbidity and temperature of the to-be-measured substance, the stirrer is configured to stir the to-be-measured substance, the coupled measuring device comprises a turbidimeter and a temperature detector, the turbidimeter comprises a probe shell made of a heat-conducting material, and the temperature detector is arranged on the inner wall of the probe shell; the stirring axis of the stirrer is configured to be arranged perpendicularly to the liquid surface of the to-be-measured substance, the turbidimeter is arranged at a certain angle with the stirrer, the probe shell of the turbidimeter is provided with a glass window for emitting light and receiving light, and the glass window is arranged on the probe shell away from the stirrer. The application can reduce the influence of the stirrer and external light on turbidity determination, and improve the measurement accuracy and measurement efficiency of solubility and solid content.

Description

Technical Field

[0001] This invention relates to the fields of chemical engineering and industrial crystallization technology, and in particular to a device, system and method for measuring solubility and solid content based on online turbidity. Background Technology

[0002] The measurement of solution turbidity has a wide range of applications, commonly used in routine water quality monitoring, environmental monitoring, industrial wastewater treatment, pharmaceuticals, and multiphase flow in the chemical industry. By measuring the turbidity data of a solution system, the solubility of chemical substances in different solvents and the solid content in suspensions can be effectively calculated.

[0003] Existing methods for measuring the solubility of substances include gravimetric methods, chromatography, refractive index methods, conductivity methods, and image methods. For example, Chinese patent application number 201910567169.8 discloses a method for measuring solubility, supersolubility, and solution concentration during crystallization based on online image analysis. This method uses an external camera to photograph the crystallization process, assesses the turbidity of the system by monitoring the number of particles, and calculates the solubility of the substance. However, due to the Rayleigh limit, optical image analysis cannot effectively monitor particles smaller than 1 micrometer, resulting in low monitoring accuracy. Chinese patent application number 201210132413.6 discloses a method for determining solubility during crystallization by measuring the conductivity of the solution. However, measuring conductivity is not applicable to non-electrolyte solution systems.

[0004] Turbidity measurement is increasingly used because the solubility of the analyte is not limited by the Rayleigh limit, it is applicable to non-electrolyte solutions, and it allows for online measurement. Turbidity measurement can be divided into offline and online measurements. Offline measurements are suitable for systems where turbidity does not change with time, temperature, or other environmental conditions, while online measurements can be used for systems where turbidity varies with different environmental conditions. Online turbidity measurement generally employs scattering, transmission, or scattering-transmission ratio methods. Among these, scattering methods measure turbidity by different angles between the incident and scattered light, including forward scattering, perpendicular scattering, and backscattering; the intensity of the scattered light is used to determine the turbidity of the solution.

[0005] Turbidimeters based on solid particle light scattering mainly consist of a light source, a receiver, and a signal processing algorithm. The intensity of the turbidity signal is affected by the characteristics of the suspended matter in the solution, the transmittance of the solvent, the hardware design of the turbidity meter, and the signal processing algorithm. For example, Chinese Patent Application No. 202121979767.5 discloses a control circuit for a turbidity meter that uses multi-beam mutual compensation technology to eliminate measurement errors caused by light window contamination. While the control circuit design considers the accuracy of measurements at low turbidity levels, it does not consider the measurement range and accuracy at high turbidity levels. Online turbidity measurements based on light scattering are also often subject to interference and limitations from devices such as stirring rods and baffles within the reaction vessel. For example, Chinese Patent Application No. 202121654283.3 discloses an online water quality turbidity meter. This meter requires a specially designed detection box and lifting plate, making it suitable for measuring the turbidity of solutions with large volumes. However, it cannot be used for online turbidity measurement in reaction vessels, especially those with a milliliter-level capacity. For example, Chinese patent application number 200910205485.7 discloses a crystallization device with an external laser generator and receiver. This device measures crystal dissolution and precipitation during crystallization by adjusting the placement of the laser generator and receiver. However, the accuracy of this method is easily affected by the built-in stirring, which can influence the light signal. Especially for smaller reaction vessels, the close proximity of the turbidimeter probe and the stirring paddle can affect the measurement light, thus impacting the accuracy of turbidity measurements. Consequently, this leads to inaccurate determinations of solubility and solid content in suspensions.

[0006] The above background information is provided only to assist in understanding the concept and technical solution of this invention. It does not necessarily belong to the prior art of this patent application, nor does it necessarily provide technical teaching. In the absence of clear evidence that the above information was disclosed before the filing date of this patent application, the above background information should not be used to evaluate the novelty and inventiveness of this application. Summary of the Invention

[0007] The purpose of this invention is to provide a device, system, and method for measuring solubility and solid content based on online turbidity, which can reduce the influence of stirrers and external light on turbidity measurement and improve the measurement accuracy and efficiency of solubility and solid content.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] An online turbidity-based solubility and solids content measurement device includes a stirrer and a container for holding the analyte, the stirrer being configured to stir the analyte, and a coupling measurement device configured to simultaneously measure the turbidity and temperature of the analyte, the coupling measurement device including a turbidimeter and a temperature detector, the turbidimeter including a probe housing made of thermally conductive material, and the temperature detector disposed on the inner wall of the probe housing;

[0010] The stirring axis of the stirrer is configured to be perpendicular to the liquid surface of the substance to be tested. The turbidimeter is set at a certain angle to the stirrer. The probe housing of the turbidimeter is provided with a glass window for emitting and receiving light, and the glass window is set on the probe housing away from the stirrer.

[0011] Furthermore, based on any or a combination of the aforementioned technical solutions, the probe housing of the turbidimeter has a columnar structure, and a circuit board, a light source generator, and a light receiver are provided inside the probe housing. The circuit board is configured to control the operation of the turbidimeter, and the circuit board is arranged perpendicular to the bottom surface of the probe housing. The light source generator and the light receiver are arranged on both sides of the circuit board.

[0012] The glass window is located on the bottom surface of the probe housing, and the direction of the emitted light from the light source generator and the surface on which the light receiver receives the light both face the glass window.

[0013] Furthermore, following any one or a combination of the aforementioned technical solutions, the probe housing is a cylindrical structure, the glass window is a circular structure concentric with the bottom surface of the probe housing, and a light-shielding plate is also provided on the probe housing, which is configured to block the portion of the glass window near the stirrer, and the light-shielding plate is perpendicular to the circuit board; and / or,

[0014] The probe housing is cylindrical, and the glass window is a semi-circular structure concentric with the bottom surface of the probe housing. Its diameter is perpendicular to the plane of the circuit board, and the glass window is located on the bottom surface of the probe housing away from the stirrer.

[0015] Furthermore, based on any or a combination of the aforementioned technical solutions, the probe housing of the turbidimeter has a columnar structure, and a circuit board, a light source generator, and a light receiver are provided inside the probe housing. The circuit board is configured to control the operation of the turbidimeter, and the circuit board is arranged perpendicular to the bottom surface of the probe housing. The light source generator and the light receiver are arranged on the same side of the circuit board.

[0016] The glass window is located on the side of the probe housing, and the direction of the emitted light from the light source generator and the surface of the light receiver that receives the light both face the glass window.

[0017] Furthermore, based on any or a combination of the aforementioned technical solutions, the included angle between the stirring axis of the stirrer and the axis of the probe housing is greater than or equal to 0° and less than or equal to 20°.

[0018] Furthermore, based on any one or a combination of the aforementioned technical solutions, the included angle ranges from greater than or equal to 2° to less than or equal to 8°.

[0019] Furthermore, following any or a combination of the aforementioned technical solutions, the light source generator and the light receiver are disposed at one end near the bottom surface of the probe housing; and / or,

[0020] The stirrer includes a controller, a motor, a stirring rod, and stirring blades mounted on the stirring rod. The controller is electrically connected to the motor and configured to control the motor to rotate. The motor shaft is connected to the stirring rod and configured to drive the stirring rod to rotate, thereby causing the stirring blades to rotate. The stirring blades are positioned below the surface of the substance to be tested; and / or,

[0021] The temperature detector is fixed to the inner wall of the probe housing by thermally conductive adhesive; and / or,

[0022] The glass window is made of high-transmittance glass.

[0023] According to another aspect of the present invention, the present invention provides a solubility and solids content measurement system based on online turbidity, comprising the solubility and solids content measurement device and display, processor, amplifier and converter as described above; wherein,

[0024] The amplifier, whose input terminal is electrically connected to the output terminal of the measuring device, is configured to sample the turbidity and temperature information of the analyte measured online by the measuring device and amplify the sampled data. The amplifier is a programmable gain amplifier with a gain coefficient ranging from 1 to 128. When the output value of the amplifier is lower than 30% of its range, its output value is automatically multiplied by 2; when the output value of the amplifier is higher than 70% of its range, its output value is automatically divided by 2.

[0025] The converter, whose input is electrically connected to the output of the amplifier, is a high-precision analog-to-digital converter configured to convert sampled data.

[0026] The processor, whose input is electrically connected to the output of the converter, is configured to receive turbidity and temperature sampling data of the substance to be tested, and to analyze and calculate the solubility and / or solid content of the substance to be tested.

[0027] The display, which is electrically connected to the processor, is configured to display the solubility and / or solid content of the substance being measured.

[0028] According to another aspect of the present invention, the present invention provides a method for measuring solubility and solid content based on online turbidity, utilizing the online turbidity-based solubility and solid content measurement system described above, wherein the solubility measurement method includes the following steps:

[0029] Prepare a suspension containing a certain initial mass of the substance to be tested, add it to the container, and configure the installation position of the stirrer and the coupling structure of the turbidimeter and temperature detector.

[0030] The stirrer is controlled to stir the suspension, and the temperature of the suspension is controlled to change from low to high, or the temperature of the suspension is controlled to change from high to low.

[0031] The turbidity data of the suspension is measured in real time by the turbidimeter, and the temperature data of the target substance is measured in real time by the temperature detector.

[0032] Calculate the mean and standard deviation of the turbidity data of the suspension. When the rate of change of the mean or standard deviation of the turbidity of the suspension over time is statistically significant, if the temperature of the suspension changes from low to high, it is determined that the solid in the suspension has dissolved; if the temperature of the suspension changes from high to low, it is determined that the solid in the suspension has crystallized.

[0033] Determine the first set of correspondences between the solubility of the substance to be tested and temperature;

[0034] Prepare a suspension containing other initial masses of the analyte, and repeat all the above steps to calculate the correspondence between the solubility of the analyte and temperature for multiple sets, thereby determining the solubility of the analyte at different temperatures.

[0035] According to another aspect of the present invention, the present invention provides a method for measuring solid content based on online turbidity, utilizing the solubility and solid content measurement system based on online turbidity as described above, the method for measuring solid content in the suspension includes the following steps:

[0036] The relationship f between turbidity and solid content in a suspension containing the analyte at a given temperature was determined using the following method:

[0037] Prepare several saturated solutions containing the analyte, add different masses of the analyte to each of the saturated solutions and stir thoroughly to form a suspension;

[0038] Measure the turbidity data for each suspension separately;

[0039] A linear regression model was used to establish the relationship f between the turbidity and solid content of the suspension of the analyte at the current temperature, where the solid content in each suspension is the mass of the analyte added to its saturated solution.

[0040] Turbidity data of suspensions containing the solids to be tested;

[0041] Based on the relationship between the turbidity and solid content of the suspension of the analyte obtained from calibration, the solid content in the suspension is determined in real time.

[0042] The beneficial effects of the technical solution provided by this invention are as follows:

[0043] a. By setting the stirrer and the turbidimeter at a certain angle, and by positioning the glass windows on the turbidimeter for emitting and receiving light away from the stirrer, the interference of the stirrer on turbidity measurement can be reduced. Furthermore, by setting a light-shielding plate on the glass windows on the turbidimeter for emitting and receiving light, the influence of external optical fibers on turbidity measurement can be further reduced, making the turbidity measurement more accurate and thus improving the accuracy of turbidity measurement of solubility and solid content.

[0044] b. This invention, by coupling a temperature detector inside the turbidimeter, can simultaneously measure the turbidity and temperature of the substance to be measured. Furthermore, the coupled measurement device has a simple structure, is suitable for measuring turbidity and temperature in reactors of various sizes, including small-volume reactors, and has high measurement efficiency.

[0045] c. The measurement system provided by the present invention uses a programmable gain amplifier for sampling, and sets that when the output value of the amplifier is lower than 30% of its range, its output value is automatically multiplied by 2, and when the output value of the amplifier is higher than 70% of its range, its output value is automatically divided by 2. By automatically adjusting the gain coefficient of the amplifier, the detection accuracy of low solid content and the detection range of high solid content can be precisely controlled.

[0046] d. This invention obtains online turbidity based on the backscattering principle. While obtaining the scattering signal, it calculates the standard deviation of the turbidity signal. When the rate of change of the mean or standard deviation of turbidity over time is statistically significant, it is determined to be the dissolution point or crystallization point, which enables precise monitoring of solid dissolution and crystallization.

[0047] e. The solid content measurement method provided by this invention obtains the relationship between turbidity and solid content through multiple sets of calibration samples, corrects the obtained relationship between turbidity and solid content through multiple sets of turbidity and solid content verification point data, and applies it to the measurement of solid content, which can effectively improve the measurement efficiency and accuracy of solid content. Attached Figure Description

[0048] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0049] Figure 1 A schematic diagram of a solubility and solids content measurement system based on online turbidity provided as an exemplary embodiment of the present invention;

[0050] Figure 2 A schematic diagram of the structure of a bottom-opening window type coupling measurement device provided as an exemplary embodiment of the present invention;

[0051] Figure 3 A schematic diagram of the structure of a side-window type coupling measurement device provided as an exemplary embodiment of the present invention;

[0052] Figure 4 A flowchart of a method for simultaneously measuring solubility and solids content, provided as an exemplary embodiment of the present invention;

[0053] Figure 5 A flowchart of a solubility measurement method provided as an exemplary embodiment of the present invention;

[0054] Figure 6 A measurement graph showing the change of turbidity and temperature of a solution over time is provided as an exemplary embodiment of the present invention;

[0055] Figure 7 A flowchart of a method for calibrating the turbidity-solids content relationship provided as an exemplary embodiment of the present invention.

[0056] The reference numerals in the attached drawings include: 100-container, 110-inner container, 120-outer container, 121-inlet end, 122-outlet end, 200-stirrer, 210-controller, 220-motor, 230-stirring paddle, 240-stirring blade, 300-turbidimeter, 310-probe housing, 311-glass window, 312-light shield, 320-circuit board, 330-light source generator, 340-light receiver, 400-temperature detector, 500-display, 600-processor, 710-outgoing light beam, 720-scattered light beam. Detailed Implementation

[0057] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0058] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, apparatus, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0059] In one embodiment of the present invention, see Figure 1A device for measuring solubility and solid content based on online turbidity is provided, capable of simultaneously measuring online changes in the dissolution, crystallization, and solid content of solid particles in a solution over time and temperature. The measuring device includes a container 100 for holding the analyte, a stirrer 200, and a coupling measuring device. Part of the stirrer 200 is disposed within the container 100 and configured to stir the analyte. The coupling measuring device is configured to simultaneously measure the turbidity and temperature of the analyte, and includes a turbidimeter 300 and a temperature detector 400 coupled to the turbidimeter 300. The temperature detector 400 can be disposed outside or inside the measuring probe of the turbidimeter 300, and the outer shell of the measuring probe of the turbidimeter 300 is made of a thermally conductive material, preferably a metal material with good thermal conductivity.

[0060] The turbidimeter 300 is positioned at a certain angle to the stirrer 200, with the angle ranging from 0° to 20°; preferably, the angle ranges from 2° to 8°. The turbidimeter 300 has a glass window 311 on its probe housing 310, positioned away from the stirrer 200. The glass window 311 is configured to provide output for emitted light 710 and input for diffused light 720. Preferably, the glass window 311 is made of high-transmittance glass, also known as ultra-clear glass, a type of ultra-transparent low-iron glass, also called low-iron glass or high-transparency glass, which has excellent light transmission properties. By positioning the turbidimeter 300 at a certain angle to the stirrer 200 and with the glass window 311 positioned away from the stirrer 200, interference with the signal during stirring can be avoided, thereby effectively improving the accuracy and efficiency of determining the solubility of substances and the solid content in suspensions.

[0061] See Figure 1In this embodiment, the container 100 is a coupled double-layer jacketed container, comprising an inner container 110 and an outer container 120. The inner container 110 is disposed inside the outer container 120, and a cavity is formed between the outer wall of the inner container 110 and the inner wall of the outer container 120. The inner container 110 is configured to hold the analyte. The outer container 120 is provided with an inlet end 121 and an outlet end 122. Preferably, the inlet end 121 is located below the outer container 120, and the outlet end 122 is located above the outer container 120. The cavity formed between the outer wall of the inner container 110 and the inner wall of the outer container 120 is configured to hold fluid. The fluid is configured to flow in from the inlet end 121 and flow out from the outlet end 122, enabling precise temperature control of the analyte solution / suspension system in the inner container 110 and improving the temperature consistency of the analyte solution / suspension system in the inner container 110.

[0062] In this embodiment, the stirrer 200 includes a controller 210, a motor 220, a stirring rod 230, and stirring blades 240 disposed on the stirring rod 230. The controller 210 is electrically connected to the motor 220 and configured to control the rotation of the motor 220. The shaft of the motor 220 is connected to the stirring rod 230 and configured to drive the stirring rod 230 to rotate, thereby causing the stirring blades 220 to rotate. The stirring blades 240 are disposed below the liquid surface of the substance to be tested. Preferably, the stirring axis of the stirrer 200 is configured to be perpendicular to the liquid surface of the substance to be tested.

[0063] In one embodiment of the present invention, see Figure 2 A bottom-opening window-type coupling measurement device is provided. The turbidimeter 300 includes a probe housing 310, a circuit board 320, a light source generator 330, and a light receiver 340, which measures turbidity based on the principle of backscattering. The probe housing 310 has a columnar structure, preferably a cylindrical structure, and is made of a material with good thermal conductivity. The circuit board 320 is configured to control the operation of the turbidimeter 300. The circuit board 320 is perpendicular to the bottom surface of the probe housing 310, that is, the plane of the substrate of the circuit board 320 is parallel to the axis of the probe housing 310. The light source generator 330 and the light receiver 340 are located on opposite sides of the circuit board 320. The light source generator 330 is configured to provide an emitted light source, and the light receiver 340 is configured to receive backscattered light through the solution.

[0064] In this embodiment, the glass window 311 is disposed on the bottom surface of the probe housing 310, and the emitted light direction of the light source generator 330 and the receiving light surface of the light receiver 340 both face the glass window 311. The temperature detector 400 is fixed to the inner wall of the probe housing 310 with thermally conductive adhesive. Preferably, the light source generator 330 and the light receiver 340 are disposed at one end near the bottom surface of the probe housing 310, that is, both the light source generator 330 and the light receiver 340 are disposed near the glass window 311 to improve the accuracy of online turbidity measurement; the temperature detector 400 is disposed at one end away from the bottom surface of the probe housing 310. Specifically, the circuit board 320 can be disposed near the bottom surface of the probe housing 310, and the temperature detector 400 can be disposed on the inner wall of the probe housing 310 above the circuit board 320.

[0065] To further reduce the impact of interference light signals and firmware such as stirrers on turbidity measurement, the turbidimeter 300 provided in this embodiment has a cylindrical probe housing 310 and a circular glass window 311 concentric with the bottom surface of the probe housing 310. A light-shielding plate 312 is also provided on the probe housing 310, configured to block the portion of the glass window 311 near the stirrer 200, and the light-shielding plate 312 is perpendicular to the circuit board 320. Preferably, the light-shielding plate 312 is a semi-circular structure concentric with the glass window 311, and its diameter is parallel to the line connecting the light source generator 330 and the light receiver 340. Alternatively, the probe housing 310 is cylindrical, and the glass window 311 is a semi-circular structure concentric with the bottom surface of the probe housing 310, its diameter is perpendicular to the plane of the circuit board 320, and the glass window 311 is located on the bottom surface of the probe housing 310 away from the stirrer 200.

[0066] In another embodiment of the present invention, unlike the coupling measurement device provided in the above embodiments which has a bottom-opening window structure, see [link to previous embodiment]. Figure 3 This embodiment provides a side-opening window type coupling measurement device. The probe housing 310 of the turbidimeter 300 has a columnar structure, preferably a cylindrical structure. Inside the probe housing 310, there is a circuit board 320, a light source generator 330, and a light receiver 340. The circuit board 320 is configured to control the operation of the turbidimeter 300. The circuit board 320 is arranged perpendicular to the bottom surface of the probe housing 310. The light source generator 330 and the light receiver 340 are arranged on the same side of the circuit board 320. The glass window 311 is arranged on the side of the probe housing 310, and the direction of the emitted light from the light source generator 330 and the surface on which the light is received by the light receiver 340 both face the glass window 311.

[0067] In one embodiment of the present invention, a system for measuring solubility and solid content based on online turbidity is provided, see [link to relevant documentation]. Figure 1 The measurement system includes an online turbidity-based solubility and solids content measurement device and display 500, processor 600, amplifier, and converter as described in any of the above embodiments. Wherein:

[0068] The amplifier, whose input is electrically connected to the output of the measuring device, is configured to sample and amplify the turbidity and temperature information of the analyte measured online by the measuring device. The amplifier is a low-noise programmable gain amplifier, which automatically adjusts the gain coefficient for scattering intensity to precisely control the detection accuracy for low solids content and the detection range for high solids content. Its gain coefficient ranges from 1 to 128. When the amplifier's output value is below 30% of its range, it automatically multiplies by 2, allowing the measurement accuracy to adapt to low solids content measurements. When the amplifier's output value is above 70% of its range, it automatically divides by 2, allowing the measurement range to automatically adapt to high solids content measurements.

[0069] The converter, whose input is electrically connected to the output of the amplifier, is a high-precision analog-to-digital converter configured to convert sampled data.

[0070] The processor 600, whose input terminal is electrically connected to the output terminal of the converter, is configured to receive turbidity and temperature sampling data of the substance to be tested, and analyze and calculate the solubility and / or solid content of the substance to be tested.

[0071] The display 500, electrically connected to the processor 600, is configured to display the solubility and / or solid content of the analyte. Obviously, the display 500 and the processor 600 can also be mobile terminals integrating computing and display functions, such as… Figure 1 The processor 600 shown also has display functionality.

[0072] In one embodiment of the present invention, see Figure 4 This paper provides a method for measuring solubility and solid content based on online turbidity. The measuring device or system described in any of the above embodiments can simultaneously measure the solubility of a substance and the solid content in a solution.

[0073] The method for measuring solubility is as follows: Figure 5 The process shown is as follows:

[0074] The installation position of the stirrer 200 and the coupling measurement device of the turbidimeter 300 and the temperature detector 400 is configured, including setting the stirrer 200 in a vertical position in the inner container 110, and the stirrer 200 and the probe housing 310 of the turbidimeter at a certain angle, and the glass window 311 is away from, i.e., facing away from, the stirrer 200.

[0075] Prepare a suspension containing a certain initial mass of the substance to be tested and add it to the container 100;

[0076] The stirrer 200 is controlled to stir the suspension, and the temperature of the suspension is controlled to change from low to high, or the temperature of the suspension is controlled to change from high to low;

[0077] The turbidity data of the suspension is measured online by the turbidimeter 300, and the temperature data of the target substance is measured in real time by the temperature detector 400.

[0078] The turbidity data obtained by sampling is processed by median filtering. When the turbidity sampling rate is F and the number of samples for median filtering is n, the sampling frequency of the effective turbidity data can be obtained as F / n.

[0079] The mean and standard deviation of the turbidity data of the suspension are calculated. When the rate of change P of the standard deviation of the turbidity of the suspension over time is statistically significant, the value of P varies slightly for different suspensions, generally ranging from 0.1% to 1%, for example, P ≤ 0.01. If the temperature of the suspension changes from low to high, it is determined that the solid in the suspension has dissolved; if the temperature of the suspension changes from high to low, it is determined that the solid in the suspension has crystallized. Specifically, the time point when the standard deviation of the turbidity signal in the solution changes less than 1% of the range (P = 0.01) can be determined as the corresponding dissolution point or crystallization point. For example, in a specific embodiment of the present invention, the changes in turbidity and temperature of a solution over time are measured as follows: Figure 6 As shown, the vertical line indicates the crystallization point of the solution at the 19th hour, when the temperature is 22°C and the turbidity is 24%. This allows us to determine the solubility of the solution at 22°C.

[0080] Determine the first set of correspondences between the solubility of the substance to be tested and temperature;

[0081] Prepare a suspension containing other initial masses of the analyte, and repeat all the above steps to calculate multiple sets of the solubility-temperature correspondence of the analyte, thereby determining the solubility of the analyte at different temperatures, and fitting the temperature-solubility curve of the analyte to obtain the temperature-solubility curve.

[0082] The method for measuring the solid content of a analyte / suspension is as follows:

[0083] See Figure 7 The relationship f between turbidity and solid content in a suspension containing the analyte at a given temperature was determined using the following method:

[0084] Prepare several saturated solutions containing the analyte, add different masses of the analyte to each saturated solution and stir thoroughly to form a suspension, which serves as a calibration sample. The calibration sample shall be no less than 5 samples.

[0085] Turbidity data for each calibration sample were measured at the same temperature and stirring speed.

[0086] The relationship f between the turbidity and solid content of the suspension of the analyte at the current temperature is established by linear regression analysis. The solid content in each suspension is the mass of the analyte added to its saturated solution. For example, the solid masses of the analyte added to the saturated solutions of the analytes numbered A1, A2, A3, A4 and A5 are m1, m2, m3, m4 and m5 respectively, and the suspensions are stirred to form the corresponding suspensions.

[0087] Prepare several saturated solutions containing the analyte, add different masses of the analyte to each saturated solution and stir thoroughly to form a suspension, which serves as a verification sample. The number of verification samples shall not be less than 5.

[0088] Turbidity data for each validation sample was measured separately to obtain multiple sets of validation point data for turbidity and solid content;

[0089] Substitute multiple sets of verification point data into the relationship f between turbidity and solid content, and correct the relationship f between turbidity and solid content obtained from the calibration sample;

[0090] A standard curve of turbidity-solid content for the analyte suspension was obtained by fitting the corrected relationship between turbidity and solid content.

[0091] Turbidity data of suspensions containing the solids to be tested;

[0092] The solid content in the current suspension is determined based on the relationship between the turbidity and solid content of the suspension of the substance to be tested after correction, or the standard curve of turbidity-solid content. The solid content and turbidity of the suspension to be tested have a one-to-one correspondence, and the solid content data can be quickly obtained from the turbidity data of the suspension.

[0093] The solubility and solids content measurement device, system and method based on online turbidity provided by this invention can accurately and efficiently measure the solubility, crystallization and solids content of various solids. The following six specific embodiments illustrate how the solubility and solids content measurement device based on online turbidity provided by this invention can measure and monitor the solubility point, crystallization point, solids content and emulsification process. Specific Implementation Example 1

[0095] 30g of taurine solid is dissolved in 100g of water to form a suspension, and the suspension is placed in the inner container 110. In this embodiment, the coupling measurement device is a bottom-opening window type coupling measurement device. The light source generator 330 and the light receiver 340 are disposed on both sides of the circuit board 320, and the glass window 311 is disposed on the bottom surface of the probe housing 310. The angle between the probe housing 310 of the turbidimeter 300 and the stirring rod is set to 20° to reduce the influence of the stirring blade and external light on the turbidity measurement process.

[0096] The temperature of the suspension in the inner container 110 is gradually increased by controlling the temperature of the fluid between the inner container 110 and the outer container 120 of the coupled double-layered jacketed container, and the changes in turbidity and temperature of the suspension over time are recorded. The point at which the standard deviation of the turbidity signal in the solution changes below 1% of the range as the temperature increases is the dissolution point of taurine in water. Specific Implementation Example 2

[0098] 10g of succinic acid solid is dissolved in 100g of water to form a suspension, and the suspension is placed in the inner container 110. In this embodiment, the coupling measurement device is a bottom-opening window type coupling measurement device. The light source generator 330 and the light receiver 340 are disposed on both sides of the circuit board 320, and the glass window 311 is disposed on the bottom surface of the probe housing 310. The angle between the probe housing 310 of the turbidimeter 300 and the stirring rod is set to 10° to reduce the influence of the stirring blade and external light on the turbidity measurement process.

[0099] The temperature of the suspension in the inner container 110 is gradually increased by controlling the temperature of the fluid between the inner container 110 and the outer container 120 of the coupled double-layered jacketed container, and the changes in turbidity and temperature of the suspension over time are recorded. The point at which the standard deviation of the turbidity signal in the solution changes below 0.1% of the range as the temperature increases is the solubility point of succinic acid in water. Specific Implementation Example 3

[0101] 30g of taurine solid is dissolved in 100g of water and placed in the inner container 110. The temperature inside the inner container 110 is controlled at 75°C to form a clear taurine solution. In this embodiment, the coupling measurement device is a side-opening window type coupling measurement device. The light source generator 330 and the light receiver 340 are located on the same side of the circuit board 320, and the glass window 311 is located on the side of the probe housing 310. Simultaneously, the probe housing 310 of the turbidimeter 300 is set parallel to the stirrer 200, i.e., the angle between them is 0°, and the glass window 311 faces away from the stirrer 200 to reduce the influence of the stirring blades and external light on the turbidity measurement process.

[0102] The temperature of the solution in the inner container 110 is gradually decreased by controlling the temperature of the fluid between the inner container 110 and the outer container 120 of the coupled double-layered jacketed container, and the changes in turbidity and temperature of the solution over time are recorded. The time point p = 0.01, where the turbidity of the solution changes significantly with time as the temperature decreases, is the crystallization point of taurine in water. Specific Implementation Example 4

[0104] 10g of taurine solid is dissolved in 100g of water and placed in the inner container 110. The temperature inside the inner container 110 is controlled at 50°C to form a clear taurine solution. In this embodiment, the coupling measurement device is a side-opening window type coupling measurement device. The light source generator 330 and the light receiver 340 are located on the same side of the circuit board 320, and the glass window 311 is located on the side of the probe housing 310. Simultaneously, the probe housing 310 of the turbidimeter 300 is set parallel to the stirrer 200, i.e., the angle between them is 0°, and the glass window 311 faces away from the stirrer 200 to reduce the influence of the stirring blades and external light on the turbidity measurement process.

[0105] The temperature of the solution in the inner container 110 is gradually decreased by controlling the temperature of the fluid between the inner container 110 and the outer container 120 of the coupled double-layered jacketed container, and the changes in turbidity and temperature of the solution over time are recorded. The time point p = 0.01, where the turbidity of the solution changes significantly with time as the temperature decreases, is the crystallization point of taurine in water. Specific Implementation Example 5

[0107] In this embodiment, based on the established solids content-turbidity standard curve, the relationship between solids content and temperature during the cooling crystallization process of taurine was determined. Five 100g portions of saturated taurine solution at 50°C were prepared, and 5g, 10g, 15g, 20g, and 25g of taurine crystals were added to the prepared saturated taurine solution, respectively. The stirring speed was adjusted to 300 rpm to ensure thorough mixing, and the turbidity values ​​were read and recorded. A linear regression model was used to establish the relationship f between the turbidity and solids content of the taurine suspension.

[0108] A crystallization solution containing 30g taurine and 100g water at 75℃ was prepared, dissolved, and then cooled for crystallization. During the crystallization process, the turbidity signal monitored online was substituted into the established solids content-turbidity relationship f of the taurine suspension to obtain the real-time solids content in the solution. Specific Implementation Example 6

[0110] Prepare 250g of a 0.3wt% ethylene glycol distearate and 0.15wt% Tween 80 aqueous solution and place it in the inner container 110 for thorough mixing. In this embodiment, the coupling measurement device is a bottom-opening window type coupling measurement device. The light source generator 330 and the light receiver 340 are disposed on both sides of the circuit board 320, and the glass window 311 is disposed on the bottom surface of the probe housing 310. The angle between the probe housing 310 of the turbidimeter 300 and the stirring rod is set to 15° to reduce the influence of the stirring blade and external light on the turbidity measurement process.

[0111] The temperature of the solution in the inner container 110 is controlled to 75°C by controlling the temperature of the fluid between the inner container 110 and the outer container 120 of the coupled double-layered jacketed container. The stirring speed inside the container is changed to 100 rpm, 150 rpm, and 300 rpm, and the changes in turbidity and the standard deviation of the turbidity signal with the stirring speed are recorded. As the stirring speed increases, the change in the standard deviation of turbidity in the solution with time becomes significant, i.e., p = 0.01 indicates ethylene glycol distearate emulsification.

[0112] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0113] The above description is only a specific embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A method for measuring solid content based on online turbidity, characterized in that, The method for measuring the solid content in a suspension includes the following steps: The relationship between turbidity and solid content in a suspension containing the analyte at a given temperature was determined using the following method. f : Prepare several saturated solutions containing the analyte, add different masses of the analyte to each saturated solution and stir thoroughly to form a suspension, which serves as the calibration sample; Measure the turbidity data for each calibration sample separately; A linear regression model was used to establish the relationship between the turbidity and solids content of the calibrated sample at the current temperature. f The solid content in each suspension is the mass of the analyte added to its saturated solution; Prepare several saturated solutions containing the analyte, add different masses of the analyte to each saturated solution and stir thoroughly to form a suspension, which serves as a verification sample; Turbidity data for each validation sample was measured separately to obtain multiple sets of validation point data for turbidity and solid content; Substituting multiple sets of verification point data into the relationship between turbidity and solids content f The relationship between turbidity and solids content obtained from the calibration samples was also analyzed. f Make corrections; A standard curve of turbidity-solid content for the analyte suspension was obtained by fitting the corrected relationship between turbidity and solid content. Turbidity data of suspensions containing the solids to be tested; The relationship between the turbidity and solid content of the suspension of the analyte obtained from calibration. f Real-time measurement of solid content in suspension.

2. The method for measuring solid content based on online turbidity according to claim 1, characterized in that, The solid content in a suspension is measured using an online turbidity-based solid content measurement system, which includes an online turbidity-based solid content measurement device. The solid content measuring device includes a stirrer (200) and a container (100) for holding the substance to be tested. The stirrer (200) is configured to stir the substance to be tested. The device is characterized by further including a coupling measuring device configured to simultaneously measure the turbidity and temperature of the substance to be tested. The coupling measuring device includes a turbidity meter (300) and a temperature detector (400). The turbidity meter (300) includes a probe housing (310) made of thermally conductive material. The temperature detector (400) is disposed on the inner wall of the probe housing (310). The stirring axis of the stirrer (200) is configured to be perpendicular to the liquid surface of the substance to be tested. The turbidimeter (300) is set at a certain angle to the stirrer (200). The probe housing (310) of the turbidimeter (300) is provided with a glass window (311) for emitting light and receiving light, and the glass window (311) is set on the probe housing (310) at a position away from the stirrer (200).

3. The method for measuring solid content based on online turbidity according to claim 2, characterized in that, The probe housing (310) of the turbidimeter (300) has a columnar structure. Inside the probe housing (310) are a circuit board (320), a light source generator (330), and a light receiver (340). The circuit board (320) is configured to control the operation of the turbidimeter (300). The circuit board (320) is arranged perpendicular to the bottom surface of the probe housing (310). The light source generator (330) and the light receiver (340) are arranged on both sides of the circuit board (320). The glass window (311) is located on the bottom surface of the probe housing (310), and the direction of the emitted light from the light source generator (330) and the surface of the light receiver (340) are both facing the glass window (311).

4. The method for measuring solid content based on online turbidity according to claim 3, characterized in that, The probe housing (310) is cylindrical, and the glass window (311) is a circular structure concentric with the bottom surface of the probe housing (310). A light-shielding plate (312) is also provided on the probe housing (310), configured to block the portion of the glass window (311) near the stirrer (200), and the light-shielding plate (312) is perpendicular to the circuit board (320); and / or, The probe housing (310) is a cylindrical structure, and the glass window (311) is a semi-circular structure concentric with the bottom surface of the probe housing (310). Its diameter is perpendicular to the plane where the circuit board (320) is located, and the glass window (311) is located on the bottom surface of the probe housing (310) on the side away from the stirrer (200).

5. The method for measuring solid content based on online turbidity according to claim 2, characterized in that, The probe housing (310) of the turbidimeter (300) has a columnar structure. Inside the probe housing (310) are a circuit board (320), a light source generator (330), and a light receiver (340). The circuit board (320) is configured to control the operation of the turbidimeter (300). The circuit board (320) is arranged perpendicular to the bottom surface of the probe housing (310). The light source generator (330) and the light receiver (340) are arranged on the same side of the circuit board (320). The glass window (311) is located on the side of the probe housing (310), and the direction of the emitted light of the light source generator (330) and the surface of the light receiver (340) are both facing the glass window (311).

6. The method for measuring solid content based on online turbidity according to any one of claims 2-5, characterized in that, The angle between the stirring axis of the stirrer (200) and the axis of the probe housing (310) is greater than or equal to 0° and less than or equal to 20°.

7. The method for measuring solid content based on online turbidity according to claim 6, characterized in that, The included angle is greater than or equal to 2° and less than or equal to 8°.

8. The method for measuring solid content based on online turbidity according to claim 5, characterized in that, The light source generator (330) and the light receiver (340) are disposed at one end near the bottom surface of the probe housing (310); and / or, The stirrer (200) includes a controller (210), a motor (220), a stirring rod (230), and stirring blades (240) disposed on the stirring rod (230). The controller (210) is electrically connected to the motor (220) and is configured to control the rotation of the motor (220). The shaft of the motor (220) is connected to the stirring rod (230) and is configured to drive the stirring rod (230) to rotate, thereby driving the stirring blades (240) to rotate. The stirring blades (240) are disposed below the liquid surface of the substance to be tested; and / or, The temperature detector (400) is fixed to the inner wall of the probe housing (310) by thermally conductive adhesive; and / or, The glass window (311) is made of high-transmittance glass.

9. The method for measuring solid content based on online turbidity according to any one of claims 6, characterized in that, It also includes displays, processors, amplifiers, and converters; among which, The amplifier, whose input terminal is electrically connected to the output terminal of the solid content measuring device, is configured to sample the turbidity and temperature information of the analyte measured online by the solid content measuring device and amplify the sampled data. The amplifier is a programmable gain amplifier with a gain coefficient ranging from 1 to 128. When the output value of the amplifier is lower than 30% of its range, its output value is automatically multiplied by 2; when the output value of the amplifier is higher than 70% of its range, its output value is automatically divided by 2. The converter, whose input is electrically connected to the output of the amplifier, is a high-precision analog-to-digital converter configured to convert sampled data. The processor, whose input is electrically connected to the output of the converter, is configured to receive turbidity and temperature sampling data of the substance to be tested, and to analyze and calculate the solubility and / or solid content of the substance to be tested. The display, which is electrically connected to the processor, is configured to display the solubility and / or solid content of the substance being measured.

Images