Temperature compensation method for parameter measurement of liquid in pipeline
By using external infrared sensors and temperature correction models, the problem of accurate measurement of liquid parameters inside the pipeline was solved, enabling rapid and accurate temperature compensation and impurity diagnosis, thereby improving the control level of the chemical process.
Patent Information
- Application Number
- CN202511031899.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-25
- Publication Date
- 2025-11-07
AI Technical Summary
In existing technologies, the measurement of liquid parameters in pipelines is affected by temperature and impurities, resulting in reduced measurement accuracy and an inability to respond promptly to temperature changes and diagnose impurities.
Direct temperature measurement is performed using an infrared sensor located outside the pipeline. A temperature correction model is established, and temperature fluctuations are analyzed using the empirical mode decomposition method to achieve accurate compensation of liquid parameters and diagnosis of impurities.
It enables rapid and accurate temperature measurement and impurity diagnosis, improving the accuracy of liquid parameter measurement and the control capability of chemical processes.
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Figure CN120907584A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the field of liquid chemical measurement, and more particularly relates to a temperature compensation method for measuring liquid parameters in a pipeline. BACKGROUND
[0002] At present, a large amount of liquid including water and various chemicals are needed in the industries of semiconductor manufacturing, solar energy manufacturing, LED manufacturing, etc. On-line real-time monitoring and measurement of liquid parameters in the production process are the key to guarantee the stable product quality and the improvement of yield. These parameters include concentration, flow rate, conductivity, pH value, density, conductivity, refractive index, etc.
[0003] Taking the measurement of chemical concentration as an example, the existing methods for measuring the concentration of liquid in a pipeline often use density method or refractive index method, or enhance a specific spectral band by using a high-stable cold light source to improve the signal-to-noise ratio of the detection signal of the specific spectral band, and then measure the mixed multi-component chemicals.
[0004] However, the accuracy of the measurement data is greatly affected by the temperature of the liquid and the impurities in the liquid, so it is necessary to monitor the temperature of the liquid in the pipeline in real time during the concentration monitoring process. If a temperature sensor is arranged in the pipeline to measure the temperature, a protective layer needs to be added outside the sensor due to the corrosiveness of the chemicals, which reduces the sensitivity or accuracy of the temperature test. If a temperature sensor is arranged outside the pipeline, it cannot respond to the temperature change of the fluid in the pipeline in time. In addition, the liquid chemicals in the pipeline may contain impurities such as bubbles and particulate matter, which causes the liquid in the pipeline to form a complex two-phase flow or multi-phase flow, which not only affects the accuracy of the concentration measurement, but also may affect the chemical process.
[0005] Therefore, there is an urgent need for a method that can accurately measure the temperature of the liquid in the pipeline for parameter compensation and timely diagnose the impurities in the pipeline. SUMMARY
[0006] The purpose of the present application is to provide a temperature compensation method for measuring liquid parameters in a pipeline, which can directly and through-obstacle measure the temperature of the liquid in the pipeline by using an infrared sensor outside the pipeline, and has a fast response speed and high accuracy compared with a contact-type measurement sensor. The temperature fluctuation is monitored to determine whether the liquid in the pipeline contains impurities. Thus, the liquid temperature can be accurately monitored, and the impurities existing in the pipeline can be diagnosed or found in time, which is beneficial to the precise control of the chemical process and improves the product control level.
[0007] The technical solutions adopted by the present application are as follows:
[0008] The temperature compensation method for measuring chemical parameters in a pipeline comprises the following steps: S1, establishing a temperature correction model; S2, measuring the temperature of the liquid in the pipeline using an infrared sensor outside the pipeline to obtain the temperature Ts measured by the sensor; S3, obtaining the actual temperature T of the measured liquid based on the temperature correction model l ; S4, compensating the measured value of the chemical parameter based on the actual temperature T l . The chemical parameter can be the concentration of the chemical, or the flow, flow rate, conductivity, pH value, density, conductivity, refractive index, etc. of the chemical.
[0009] Optionally, the temperature correction model is shown in formula (1):
[0010]
[0011] wherein, T l is the actual temperature of the liquid in the pipeline, T e is the ambient temperature of the pipeline, T s is the temperature of the liquid measured by the sensor, w is the thickness of the pipeline, ρ is the density of the liquid, k i is the correction coefficient related to the measured liquid, k e is the correction coefficient related to the pipeline material, Δt is the time interval, and k0 is the correction coefficient related to the installation distance.
[0012] Optionally, the distance between the infrared sensor and the outer surface of the pipeline is between 0-12mm.
[0013] Optionally, the infrared sensor only receives infrared radiation within a certain angle range, thereby measuring the temperature of the fluid in the pipeline in a directional manner.
[0014] Optionally, the angle range is between 0°-90°, and the infrared radiation outside the angle range does not interfere with the temperature measurement.
[0015] Optionally, the temperature compensation method further comprises: analyzing and judging the characteristics of the fluid in the pipeline based on the Ts sequence composed of multiple temperature values Ts measured by the infrared sensor.
[0016] Optionally, the temperature compensation method analyzes the multiple temperature values Ts measured by the infrared temperature sensor based on the empirical mode decomposition method (EMD) to obtain the decomposed data layer characteristics.
[0017] Optionally, the data layer characteristics include at least one of temperature fluctuation, temperature change trend, and accurate temperature value.
[0018] Optionally, the fluid characteristic refers to a two-phase flow characteristic and / or a multi-phase flow characteristic, and when the measured temperature fluctuation value exceeds a threshold value of temperature fluctuation, the liquid in the pipeline contains impurities and / or bubbles.
[0019] The present application has the following technical effects:
[0020] The present application directly and through the barrier measures the temperature of the liquid in the pipeline, realizes fast response speed, no lag and high precision in temperature measurement, thereby reducing the influence of temperature error on concentration monitoring, PH measurement, flow rate, density, conductivity, refractive index and other parameter measurement; the temperature correction model of the present application has high precision matching and adaptability for specific liquid and pipeline; and the temperature fluctuation analysis is beneficial to the precise control of the chemical process. BRIEF DESCRIPTION OF DRAWINGS
[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.
[0022] Figure 1 The flow chart of the temperature compensation method in the chemical parameter measurement in the pipeline of the present application;
[0023] Figure 2 The temperature fluctuation and analysis map of the liquid with impurities in the pipeline;
[0024] Figure 3 The temperature fluctuation and analysis map of the liquid without impurities in the pipeline;
[0025] Figure 4 The position diagram of the temperature sensor and the pipeline of the present application. DETAILED DESCRIPTION
[0026] The technical solutions in the embodiments of the present application will be described clearly and completely in the following with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.
[0027] Figure 1 The flow chart of the temperature compensation method in the chemical parameter measurement in the pipeline of the present application is shown, and the method comprises the following steps:
[0028] In step 110, a temperature correction model is established for correcting the measurement of the temperature sensor to obtain the actual temperature of the liquid in the pipeline. The temperature correction model can be established offline, and preferably, the model is refined for a specific pipeline and fluid category to obtain accurate radiation coefficients and background parameters. Once the temperature correction model is obtained, frequent temperature correction is not required.
[0029] In some embodiments, the temperature correction model is determined based on the characteristics of the liquid in the pipeline and the characteristics of the pipeline. Preferably, the temperature correction model is as shown in formula (1):
[0030]
[0031] wherein, T l represents the actual temperature of the liquid in the pipeline, T e represents the ambient temperature of the pipeline, T s represents the liquid temperature measured by the sensor, w represents the thickness of the pipeline, p represents the density of the liquid, k l is a correction coefficient related to the measured liquid, k e is a correction coefficient related to the pipeline material, and At is the time interval, k0 is a correction coefficient related to the installation distance. The three correction coefficients can be determined by experiments.
[0032] In some embodiments, the specific steps for establishing the correction model are as follows: a first set of measurement values at multiple time points or multiple fluid positions are obtained using a temperature sensor placed in the pipeline, then a second set of measurement values are obtained by using an infrared temperature sensor to measure the corresponding time points or fluid positions, the first set of measurement values are used to correct the second set of measurement values, and the temperature correction model is established by least squares fitting of multiple measurement values.
[0033] In step 120, the temperature of the liquid in the pipeline is measured using an infrared sensor outside the pipeline to obtain the temperature Ts measured by the sensor. The infrared temperature sensor is placed outside the pipeline to be measured, and preferably, the infrared temperature sensor is between 0-12 mm from the outer surface of the pipeline, and more preferably, the infrared temperature sensor is between 3-5 mm from the outer surface of the pipeline, for example, 5 mm.
[0034] The positional relationship between the infrared sensor and the pipeline is shown in Figure 4 , wherein 410 is the infrared sensor and 420 is the pipeline wall.
[0035] In some embodiments, the infrared temperature sensor can measure the temperature of the fluid in the pipeline in a directional manner, which means that only infrared radiation within a certain spatial angle range is received, and preferably, the angle range is between 0°-90°, and infrared radiation outside the angle range does not interfere with the temperature measurement.
[0036] The distance between the infrared sensor and the pipe, and the range of the receiving angle, depend on one or more of the following: pipe thickness, pipe diameter, liquid flow velocity inside the pipe, liquid density inside the pipe, and outer surface temperature of the pipe.
[0037] In step 130, the actual temperature T of the liquid being measured is obtained based on the temperature correction model. l Furthermore, this temperature value is applied to the monitoring of liquid parameters, such as concentration monitoring, pH measurement, flow rate, density, conductivity, and refractive index. Taking the measurement of chemical concentration in a pipeline using spectroscopy as an example, the measurement of chemical concentration in a pipeline is mainly based on infrared spectral absorbance. Changes in liquid temperature will significantly affect the accuracy of infrared spectral absorbance measurement. In addition, temperature also has a certain impact on the actual concentration value of the liquid. The influence of temperature is quantified and removed experimentally to compensate for the concentration. At this point, the actual temperature needs to be obtained. The temperature compensation formula for chemical concentration is:
[0038]
[0039] Among them, C r T represents the actual concentration of chemicals inside the pipeline. l This indicates the actual temperature of the liquid inside the pipe, C. m The concentration of chemicals inside the pipeline is measured by infrared spectroscopy absorption. The compensation coefficient was determined experimentally.
[0040] In step 140, based on multiple temperature values Ts measured by the infrared sensor at different time points, the measured values of the infrared temperature sensor are analyzed using Empirical Mode Decomposition (EMD). The characteristics of the fluid inside the pipe are determined from the features of the decomposed data layers. The features of the data layers can be one or more of temperature fluctuations, temperature change trends, and precise temperature values. Further, based on the features of the data layers, preferably based on temperature fluctuations and temperature change trends, the characteristics of the fluid inside the pipe are analyzed and determined. For example, it is determined whether the fluid inside the pipe is a two-phase flow or a multiphase flow. If so, it indicates that there are bubbles, particles, or other impurities in the liquid inside the pipe.
[0041] It should be noted that the above process relationships are merely illustrative and do not constitute a limitation of the present invention. For example, to determine the temperature value of the liquid in the pipeline, steps 110, 120, and 130 can be performed. For impurity diagnosis, steps 120 and 140 can be performed.
[0042] In some embodiments, a threshold of temperature fluctuation can be set, for example, the threshold of temperature fluctuation is ±0.05, when the measured temperature fluctuation exceeds the threshold, it indicates that there is impurity in the liquid in the pipeline, and the real-time diagnosis or discovery of whether there is impurity in the liquid is achieved. In some embodiments, when the temperature fluctuation does not conform to the periodic law, it can also be determined that there is impurity in the liquid.
[0043] Figure 2 、 Figure 3 The temperature fluctuation and analysis graph of the liquid in the pipeline with or without impurity are shown. The temperature of the liquid in the pipeline is recorded every 1s, and a total of 1600s is recorded to form a Ts sequence composed of multiple temperature values Ts, Figure 2 and Figure 3 Three groups of data, i.e. the original temperature data and two groups of analysis data, are shown. Specifically, the original temperature data is decomposed into several intrinsic mode functions (IMF), each of which represents the composition of the signal at different time scales and frequencies. The arrangement of these IMFs from the highest frequency to the lowest frequency constitutes the decomposition of the signal, in which the IMF obtained by the first decomposition has a higher frequency and a shorter time scale, and the last IMF has a lower frequency and a longer time scale. Among them, IMF7 and IMF8 are intrinsic mode functions (IMF) obtained by empirical mode decomposition (EMD) of the original temperature data of the liquid.
[0044] Exemplarily, from the IMF7 of Figure 2 , it can be seen that the liquid temperature fluctuates within ±0.1℃, which is far more than ±0.05℃, indicating that the liquid in the pipeline contains impurities at this time.
[0045] Exemplarily, from the IMF7 of Figure 3 , it can be seen that the fluctuation range of the liquid temperature is far less than 0.05℃, indicating that the liquid in the pipeline does not contain impurities at this time.
[0046] The preferred embodiments disclosed above are only used to help explain the present application. The preferred embodiments do not describe all the details and do not limit the application to the specific embodiments described. Obviously, many modifications and changes can be made according to the content of the present application. The embodiments are selected and described in detail in order to better explain the principles and practical applications of the present application, so that those skilled in the art can well understand and utilize the present application. The present application is limited only by the claims and their full scope and equivalents.
Claims
1. A method of temperature compensation for measuring a parameter of a fluid in a pipe, the method comprising: The method comprises the following steps: S1, establishing a temperature correction model; S2, using an infrared sensor outside the pipeline to measure the temperature of the liquid inside the pipeline, and obtaining a temperature Ts measured by the sensor; S3, based on the temperature correction model, obtaining the actual temperature T of the liquid in the pipeline l ; S4, based on the actual temperature T l The measured values of the liquid parameters are compensated.
2. The temperature compensation method according to claim 1, wherein the temperature correction model where T l represents the actual temperature of the liquid in the pipe, T e represents the ambient temperature of the pipe, T s represents the temperature measured by the sensor, w represents the thickness of the pipe, p represents the density of the liquid, k l is a correction coefficient related to the liquid being measured, k e is a correction coefficient related to the pipe material, and At is the time interval, and k0 is a correction coefficient related to the installation distance.
3. The temperature compensation method of claim 1, wherein, The infrared sensor is 0-12 mm away from the outer surface of the pipeline.
4. The temperature compensation method of claim 1, wherein, The infrared sensor only receives infrared radiation within a certain angle range, thereby measuring the temperature of the fluid in the pipeline in a directional manner.
5. The temperature compensation method of claim 4, wherein, The angle range is 0°-90°, and infrared radiation outside the angle range does not interfere with the temperature measurement.
6. The temperature compensation method of claim 1, wherein, The liquid parameter is any one or a combination of concentration, pH value, flow rate, density, conductivity, and refractive index.
7. The temperature compensation method according to claim 1, further comprising: Based on the temperature value sequence Ts measured by the infrared sensor, analyzing and determining the characteristics of the fluid in the pipeline.
8. The temperature compensation method of claim 7, wherein: Based on the empirical mode decomposition method, analyzing the Ts sequence composed of the plurality of temperature values Ts measured by the infrared temperature sensor, and obtaining decomposed data layer characteristics.
9. The temperature compensation method of claim 8, wherein: The data layer characteristics include at least one of temperature fluctuation, temperature change trend, and accurate temperature value.
10. The temperature compensation method of claim 7, wherein: The fluid characteristics refer to two-phase flow characteristics and / or multi-phase flow characteristics, and the fluid characteristics are used to determine whether the liquid in the pipeline contains impurities and / or bubbles.
11. The temperature compensation method of claim 9, wherein: When the measured temperature fluctuation value exceeds the threshold value of the temperature fluctuation, the liquid in the pipeline contains impurities and / or bubbles.