A boiler water quality hardness on-line detector and method based on lambert beer's law

Abstract

The present application relates to the technical field of water quality detection, in particular to a boiler water quality hardness on-line detector and method based on Lambert-Beer law, which comprises an equipment shell box, an optical module, a fluid control module, a self-cleaning module, a compensation algorithm unit, a data transmission unit, a touch control screen and a warning unit; the optical module comprises an LED light source and an optical probe, the LED light source is used for providing light required for detection, and the optical probe is used for receiving light and collecting absorbance signals. In the boiler water quality hardness on-line detector and method based on Lambert-Beer law, the dual-wavelength anti-interference design eliminates error sources: the optical module adopts a combination of a 520±5nm main wavelength and a 700±10nm reference wavelength, and cooperates with the compensation algorithm unit to calculate and correct the absorbance, so that the interference caused by suspended solids and bubbles in the boiler water sample can be accurately deducted.

Description

Technical Field

[0001] This invention relates to the field of water quality testing technology, and more specifically, to an online boiler water hardness tester and method based on Lambert-Beer's law. Background Technology

[0002] As core equipment in industrial production and energy supply, the operational safety and energy efficiency of boilers directly depend on the precise control of influent water quality. Water hardness is a key indicator determining boiler lifespan and operating costs. According to the mandatory requirements of the GB / T 1576-2018 standard for industrial boiler water quality, the total hardness of influent water for steam and hot water boilers must be strictly controlled to ≤0.6 mmol / L. If this standard is exceeded, calcium and magnesium ions in the water will form dense scale on the inner wall of the boiler tubes, leading to a decrease in heat transfer efficiency of more than 15%. This not only wastes energy but may also cause major safety accidents such as localized overheating and boiler tube rupture. A food factory's 2.0MPa steam boiler suffered a direct economic loss of over 200,000 yuan after one year due to scale buildup exceeding 3mm in its boiler tubes caused by long-term excessive hardness. Such cases are common in the industrial sector.

[0003] Currently, boiler water hardness testing mainly relies on traditional testing methods and early online equipment, which have many technical bottlenecks. Laboratory testing primarily uses EDTA complexometric titration, which requires manual water sample collection, addition of chrome black T indicator, and visual judgment of the endpoint color change. This method not only has a testing cycle of over 30 minutes but is also prone to errors due to operator subjective judgment and deviations in indicator dosage. Especially in high-alkalinity water samples, the endpoint color is prone to repeated drift, seriously affecting data reliability. This offline testing mode cannot achieve real-time monitoring, making it difficult to detect water quality exceeding standards in a timely manner and creating safety hazards.

[0004] While existing online monitoring equipment can achieve continuous monitoring, it suffers from significant shortcomings in accuracy, stability, and intelligence. Some devices employ a single light source detection scheme, which is susceptible to interference from suspended solids, bubbles, and other factors in boiler water samples, often resulting in detection errors exceeding ±5%. Most devices lack effective temperature compensation mechanisms, and the drift of the molar absorptivity with temperature further reduces detection accuracy. Furthermore, existing equipment generally suffers from high maintenance costs: optical probes are easily affected by scale buildup, requiring regular manual disassembly and cleaning; reagent injection volume control accuracy is insufficient (errors often ≥ ±5%), leading to waste of Chrome Black T colorimetric reagent and affecting reaction sufficiency. In addition, while some imported equipment offers higher accuracy, its high price and data transmission protocols incompatible with mainstream domestic boiler DCS systems make it difficult to meet the cost-effectiveness requirements of industrial applications. Summary of the Invention

[0005] The purpose of this invention is to provide an online boiler water hardness tester and method based on Lambert-Beer's law, in order to solve the problem that although existing online testing equipment can achieve continuous monitoring, it has obvious deficiencies in accuracy, stability and intelligence.

[0006] To achieve the above objectives, the present invention provides an online boiler water hardness detector based on Lambert-Beer's law, comprising an equipment housing, an optical module, a fluid control module, a self-cleaning module, a compensation algorithm unit, a data transmission unit, a touch control screen, and an early warning unit;

[0007] The optical module includes an LED light source and an optical probe. The LED light source is used to provide the light required for detection, and the optical probe is used to receive the light and collect the absorbance signal.

[0008] The fluid control module includes a peristaltic metering pump, a reagent bottle, a volumetric cavity, a water inlet, a water outlet, a drain valve, and a stirring pump. The water inlet is used to receive boiler water samples and transport them to the volumetric cavity. The water outlet is used to discharge the rinsing liquid, reaction liquid, and cleaning waste liquid from the volumetric cavity. The drain valve is used to control the opening and closing of the water outlet. The reagent bottle is used to store Chrome Black T colorimetric reagent. The peristaltic metering pump is used to quantitatively extract the colorimetric reagent from the reagent bottle and inject it into the volumetric cavity through the reagent inlet. The stirring pump is used to stir the water sample and colorimetric reagent in the volumetric cavity to ensure thorough mixing and reaction.

[0009] The touchscreen control screen has a built-in program that controls the equipment's operation: during operation, it controls the inlet to let water in, and after the water sample enters the volumetric cavity, it is discharged through the outlet for rinsing. After a set time, it controls the drain valve to close. Then, it controls the peristaltic metering pump to inject the colorimetric reagent from the reagent bottle into the volumetric cavity and controls the stirring pump to start stirring. At the same time, the program can receive signals collected by the optical probe and LED light source, analyze and detect the signals to obtain water hardness data, and display the water hardness data in real time on the touchscreen control screen.

[0010] This setup constructs an integrated architecture of "optical detection + fluid control + intelligent control." The LED light source of the optical module provides the specific light required for detection, and the optical probe receives the light and converts it into absorbance signals, providing basic data for water hardness calculation. The fluid control module realizes the transportation, reaction, and discharge of water samples through components such as inlet, volume chamber, and outlet. The peristaltic metering pump precisely controls the injection amount of colorimetric reagent, and the stirring pump ensures that the water sample and colorimetric reagent are fully mixed and reacted. The touch screen control screen has a built-in program as the core control unit, which coordinates the operation of each module and realizes process automation and data processing and analysis.

[0011] Based on Beer-Lambert's law, light is emitted through an LED light source. The light passes through a mixture of water sample and colorimetric reagent in a volumetric cavity. An optical probe collects the absorbance signal. The built-in program on the touch control screen calculates the water hardness data based on the correlation between absorbance and water hardness.

[0012] The touch control screen has a built-in program with preset operating logic. First, it controls the water inlet to flush the volume chamber, removing residual impurities to avoid interfering with the detection. Then, it injects color developer through a peristaltic metering pump and stirs the reaction through a stirring pump. Finally, it completes the detection and data display, forming a complete detection closed loop.

[0013] As a preferred embodiment of the present invention, the early warning unit is linked with the built-in program of the touch control screen. When the water hardness data is unqualified, the early warning unit issues an early warning. The built-in program of the touch control screen can also control the equipment to perform the start-up flushing process. When starting up, it controls the water inlet to enter and the water outlet to exit, flushing the volume chamber and the optical probe to protect the optical probe. The data transmission unit is equipped with switch output and 4-20mA signal output functions and supports RS485 communication protocol. The switch output function can be used to cut off the boiler water inlet pipe when the early warning unit issues an early warning to ensure the safety of the boiler water quality. The compensation algorithm unit is used to correct interference factors in the detection process and improve detection accuracy.

[0014] This feature includes a built-in program on the touchscreen control panel that presets a water hardness threshold. It compares the measured data with this threshold in real time, triggering an alarm unit when the data fails to meet the standard. Simultaneously, the program activates the data transmission unit, sending a signal to the inlet pipe control component via a switch output to shut off the pipe. Upon power-up, the built-in program on the touchscreen control panel prioritizes the flushing process, using water samples to rinse the volumetric cavity and optical probe, removing scale and impurities accumulated during long-term downtime. This prevents these deposits from adhering to the optical probe surface and affecting light reception, protecting the core detection components. The compensation algorithm unit addresses interference factors such as temperature changes and suspended solids during detection, using a specific algorithm model to correct the collected absorbance signal, offsetting interference and improving data accuracy. The data transmission unit supports multiple signal outputs and communication protocols, transmitting test data via 4-20mA analog signals, RS485 communication, and other methods to enable data interaction with external systems.

[0015] In a preferred embodiment of the present invention, the LED light source includes a main wavelength LED light source and a reference wavelength LED light source, wherein the main wavelength LED light source has a wavelength of 520±5nm and the reference wavelength LED light source has a wavelength of 700±10nm; the optical probe integrates a high-sensitivity photodetector, which can receive the light from the main wavelength LED light source and the reference wavelength LED light source respectively, and collect the absorbance of the main wavelength LED light source. and reference wavelength absorbance .

[0016] This setting matches the absorption peak of the chrome black T-calcium-magnesium complex to the main wavelength LED light source, and is used to collect absorbance directly related to water hardness. The reference wavelength LED light source is less affected by calcium and magnesium ions and mainly collects the absorbance caused by interference factors such as suspended solids and bubbles in the water sample. By comparing the absorbance data of two wavelengths, the effective signal and the interference signal are separated. The high-sensitivity photodetector integrated in the optical probe can convert weak light signals into clear electrical signals, accurately capture absorbance changes at different wavelengths, and avoid signal distortion caused by insufficient detector sensitivity.

[0017] In a preferred embodiment of the present invention, the volumetric cavity also integrates a constant-temperature reaction chamber and a PT1000 temperature sensor. The constant-temperature reaction chamber is used to control the temperature of the water sample and colorimetric reagent mixing reaction within the volumetric cavity, with the controlled temperature being 50±0.5℃. The PT1000 temperature sensor is used to collect real-time temperature data within the volumetric cavity. The compensation algorithm unit can call upon the temperature data collected by the PT1000 temperature sensor to dynamically correct the drift of the molar absorptivity ε value, and simultaneously adjust the absorbance based on the dominant wavelength. and reference wavelength absorbance Calculate the corrected absorbance to deduct interference from suspended matter.

[0018] This unit features an integrated constant-temperature reaction chamber within the volumetric cavity. Heating and temperature control elements maintain the reaction temperature at 50±0.5℃. At this temperature, the complexation reaction rate of chrome black T with calcium and magnesium ions is stable and complete, preventing the colorimetric agent from failing due to excessively high temperatures or the reaction from being incomplete due to excessively low temperatures. A PT1000 temperature sensor collects real-time temperature data within the volumetric cavity. A compensation algorithm unit dynamically corrects the ε value based on a correlation model between temperature and the molar absorptivity ε, offsetting the impact of temperature changes on absorbance calculations. The compensation algorithm unit utilizes the dominant wavelength absorbance... and reference wavelength absorbance The difference or specific proportional relationship is used to calculate the corrected absorbance and deduct the interference of suspended matter on light scattering and absorption.

[0019] As a preferred embodiment of the present invention, the self-cleaning module includes an ultrasonic transducer and a backwash flow path. The ultrasonic transducer is disposed around the optical probe and is used to clean the optical probe and the inner wall of the volumetric cavity. The backwash flow path is connected to a high-pressure air source and a sampling pipeline and is used to backwash the sampling pipeline through a high-pressure air pulse. The touch control screen has a built-in program that can control the self-cleaning module to start and clean the equipment periodically.

[0020] This setup utilizes an ultrasonic transducer to generate high-frequency vibrations, which are transmitted to the surface of the optical probe and the inner wall of the volumetric cavity. This vibration causes adhering scale and impurities to detach, achieving contactless cleaning and avoiding wear and tear on components caused by mechanical cleaning. The backwash path is connected to a high-pressure air source, periodically introducing high-pressure air pulses into the sampling pipeline. The airflow's impact force removes residual water and impurities from the pipeline, preventing blockages. The touchscreen control panel has a built-in program that presets cleaning cycles; the ultrasonic transducer and high-pressure backwash path automatically activate at the designated times, requiring no manual intervention.

[0021] As a preferred embodiment of the present invention, the sampling error of the peristaltic metering pump is ≤±2%, and the amount of colorimetric reagent injected into the volumetric cavity from the reagent bottle in a single injection is controlled within a reasonable range, ensuring that the water sample and the colorimetric reagent react fully and reducing reagent consumption; the volumetric cavity is sealed to the optical probe to prevent leakage of water sample or colorimetric reagent.

[0022] This peristaltic metering pump achieves quantitative extraction and injection of the colorimetric reagent by precisely controlling the squeezing amount and frequency of the pump tube. Its structural design reduces flow fluctuations and ensures that the dosage error for each injection is ≤±2%. The volumetric cavity and optical probe are connected by a sealed component with precision-machined mating surfaces to reduce gaps and prevent leakage of water samples or colorimetric reagent, thus avoiding insufficient dosage and environmental pollution caused by leakage.

[0023] As a preferred embodiment of the present invention, the built-in program of the touch control screen can set the water inlet duration, rinsing time, drain valve closing time, peristaltic metering pump injection dosage and stirring pump stirring duration. At the same time, it can record historical detection data during equipment operation, including water hardness data, detection time and equipment operating status data. The historical detection data can be exported through RS485 communication protocol.

[0024] This feature includes a touchscreen control panel with a built-in program providing parameter settings. Operators can adjust parameters such as influent duration and rinsing time to optimize the testing process based on water sample characteristics and testing requirements. The program has a built-in storage module that records test data and equipment operating status in real time. It also connects to an external storage device via RS485 communication protocol to export data.

[0025] As a preferred embodiment of the present invention, in addition to being configured with switch output, 4-20mA signal output function and supporting RS485 communication protocol, the data transmission unit also supports Modbus protocol transmission, which can upload water hardness data to the boiler DCS system or external monitoring system, with a data transmission rate ≥9600bps and a data transmission error ≤0.1%.

[0026] This data transmission unit incorporates multiple communication protocol chips and signal conversion circuits to convert detection data into various formats, including 4-20mA analog signals, Modbus protocol data, and RS485 protocol data, adapting to the interface requirements of different external systems. By optimizing circuit design and signal processing algorithms, the data transmission rate is improved while reducing signal attenuation and interference during transmission, ensuring a data transmission error of ≤0.1%.

[0027] This invention also provides an online method for detecting boiler water hardness, used in an online boiler water hardness detector based on Lambert-Beer's law, comprising the following steps:

[0028] S1: When the equipment is turned on, the built-in program on the touch control screen starts the start-up flushing process, controls the water inlet to open, and the boiler water sample enters the volume chamber. At the same time, it controls the drain valve to open, and the liquid in the volume chamber is discharged through the water outlet to flush the volume chamber and optical probe. After the flushing is completed, it enters the standby state.

[0029] S2: During testing, the built-in program on the touch control screen controls the water inlet to open, allowing the water sample to enter the volume chamber. Then, the water outlet is controlled to discharge the water sample for rinsing. After the set rinsing time is reached, the drain valve is controlled to close.

[0030] S3: The built-in program of the touch control screen controls the peristaltic metering pump to start, quantitatively extracting the Chrome Black T colorimetric reagent from the reagent bottle and injecting it into the volume chamber. Then, it controls the stirring pump to start, stirring the water sample and colorimetric reagent in the volume chamber to make them fully mixed and react.

[0031] S4: Activate the LED light source, and the light shines on the mixed liquid in the volume chamber. The optical probe receives the light transmitted through the mixed liquid, collects the absorbance signal, and transmits it to the built-in program on the touch control screen.

[0032] S5: The touchscreen control panel's built-in program analyzes and detects the absorbance signal, and, combined with the correction data from the compensation algorithm unit, calculates the boiler water hardness value. The value is calculated in mg / L and displayed in real time on the touch control screen;

[0033] S6: The built-in program on the touch control screen judges the water hardness value. If the water hardness value is not up to standard, the control warning unit issues a warning, and at the same time the data transmission unit cuts off the boiler water inlet pipe through the switch output function.

[0034] S7: After the test is completed, the built-in program on the touch control screen controls the drain valve to open, and the reaction liquid in the volume chamber is discharged through the outlet, completing one test process;

[0035] S8: The self-cleaning module is activated periodically via the built-in program on the touch control screen to clean the optical probe, volume chamber, and sampling pipeline. At the same time, the equipment is calibrated periodically using a standard hardness solution to ensure detection accuracy.

[0036] As a preferred embodiment of the present invention, in step S4, the LED light source operates in a time-division multiplexing mode. First, the main wavelength LED light source is turned on, and the optical probe collects the absorbance of the main wavelength. Then switch to the reference wavelength LED light source, and the optical probe collects the absorbance at the reference wavelength. In step S5, the built-in program of the touch control screen (2) calculates and corrects the absorbance. k is the turbidity correction coefficient, ranging from 0.95 to 1.05, and the equation is fitted according to the calibration curve. Calculate water hardness value, correlation coefficient The start-up and rinsing process duration in step S1 and the rinsing time in step S2 can be set via the built-in program on the touch control screen, with a setting range of 1-5 minutes. In step S3, the mixing reaction temperature of the water sample and the color developer is controlled at 50±0.5℃, and the reaction time is controlled at 3-5 minutes. In step S8, the cleaning cycle of the self-cleaning module is set to 24 hours, the single cleaning time is 3-5 minutes, and the cleaning waste liquid is discharged through the outlet.

[0037] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0038] I. In this online boiler water hardness detector and method based on Lambert-Beer's law, a dual-wavelength anti-interference design eliminates error sources: the optical module uses a combination of a 520±5nm main wavelength and a 700±10nm reference wavelength, which, together with the compensation algorithm unit, calculates and corrects the absorbance. It can accurately deduct interference from suspended solids and air bubbles in boiler water samples. Under high turbidity conditions of 20 NTU, the detection error can still be controlled within ±2.3%, which is more than 50% higher than the error of more than ±5% of traditional single light source equipment. It fully meets the stringent requirements for hardness testing in GB / T 1576-2018 Industrial Boiler Water Quality.

[0039] The PT1000 temperature sensor integrated into the volumetric cavity acquires the reaction temperature in real time, and the compensation algorithm unit dynamically corrects the drift of the molar absorptivity ε value, avoiding the detection deviation caused by temperature changes in traditional equipment. Under constant temperature reaction control of 50±0.5℃, the consistency error of detection data under different temperature conditions is ≤±1.5%, ensuring the reliability of data during long-term operation.

[0040] The peristaltic metering pump has a sampling error of ≤±2%, ensuring precise injection of Chrome Black T colorimetric reagent and avoiding incomplete reaction caused by excessive or insufficient reagent; combined with the calibration curve fitting equation Detection range covers Completely covers the hardness of industrial boiler water The limit range, the deviation between a single test data and the true value of the standard solution. It is better than the error level of ±3% of laboratory titration.

[0041] II. In this online boiler water hardness testing instrument and method based on Lambert-Beer's law, the self-cleaning system, composed of an ultrasonic transducer around the optical probe and a high-pressure air backflow path, is activated periodically via a built-in program on a touch-screen control panel. A single cleaning session of 3-5 minutes can remove scale buildup on the surface of the optical probe and the inner wall of the volumetric cavity. Compared to traditional online equipment that requires manual disassembly and cleaning every month, this invention extends the maintenance cycle to more than 6 months, reducing maintenance frequency by 10-11 times per year and saving over 80% in labor costs. It also avoids equipment wear and tear caused by frequent disassembly, extending the service life of core components such as the optical probe and volumetric cavity. The combination of miniaturized flow path design and precise control by peristaltic metering pump requires only <0.1mL of Chrome Black T colorimetric reagent per test, reducing reagent costs by more than 80% compared to the 0.5-1mL / test reagent consumption of traditional online equipment. Based on an average of 24 tests per day and 300 days of operation per year, the annual reagent cost per unit can be controlled within 100 yuan, far lower than the 500-1000 yuan / year reagent expenditure of traditional equipment, significantly reducing the operating costs of small and medium-sized enterprises.

[0042] Third, in this online boiler water hardness detector and method based on Lambert-Beer's law, the touch-screen control panel with built-in programs automates the entire process from startup flushing, water sample collection, reagent injection, stirring reaction, absorbance detection, and data display, eliminating the need for manual intervention. The device automatically initiates a flushing process upon startup, starting water inlet and draining water outlet, preventing residual scale from affecting the detection accuracy of the optical probe. Compared to traditional equipment requiring manual flushing, this reduces manual operation by over 90%.

[0043] The data transmission unit supports 4-20mA analog signals, Modbus protocol, and RS485 communication protocol, with a data transmission rate ≥9600bps and an error ≤0.1%. It can seamlessly connect to mainstream domestic boiler DCS systems or external monitoring platforms to achieve real-time uploading and remote monitoring of water hardness data. Compared to some imported equipment that only supports dedicated protocols and requires additional conversion modules, this invention eliminates protocol conversion costs and avoids data delays during conversion, meeting the real-time requirements for online monitoring data in the "Guiding Opinions on the Construction of Smart Power Plants".

[0044] The touch control screen can store at least one year of historical testing data and supports export via RS485 protocol, which facilitates enterprises to analyze water quality change trends and trace equipment maintenance records. The built-in embedded processor can diagnose the operating status of components such as optical probes and peristaltic metering pumps in real time. When abnormalities occur, the warning unit will issue audible and visual prompts to avoid detection interruptions caused by equipment failure and improve the reliability of equipment operation.

[0045] IV. In this online boiler water hardness detector and method based on Lambert-Beer's Law, when excessive water hardness is detected, the early warning unit immediately issues an audible and visual warning. Simultaneously, the data transmission unit cuts off the boiler inlet pipe via a switch output function, preventing excessive water from entering the boiler and causing scaling. Combined with real-time monitoring capabilities, compared to the detection lag of over 2 hours in traditional laboratory titration methods, it achieves "second-level response and minute-level handling" for excessive hardness, reducing the risk of boiler scaling by more than 90%. The entire device complies with the safety standard of "NB / T 42040-2014 Boiler Online Monitoring Device". The sealed design of the volumetric cavity and optical probe, and the high-temperature resistant quartz material are suitable for high-temperature boiler water sample conditions, avoiding safety accidents caused by equipment leakage or material failure, and ensuring the stable operation of the boiler system. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0047] The meanings of the labels in the diagram are as follows:

[0048] 1. Equipment housing; 2. Control screen; 3. Reagent bottle; 4. Peristaltic metering pump; 5. Optical probe; 6. Stirring pump; 7. Volumetric cavity; 8. Reagent inlet; 9. Water inlet; 10. LED light source; 11. Water outlet. Detailed Implementation

[0049] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 are within the scope of protection of the present invention.

[0050] This invention provides an online boiler water hardness detector based on Beer-Lambert's law, such as... Figure 1 As shown, it includes a device housing, an optical module, a fluid control module, a self-cleaning module, a compensation algorithm unit, a data transmission unit, a touch control screen 2, and an early warning unit;

[0051] The optical module includes an LED light source 10 and an optical probe 5. The LED light source 10 is used to provide the light required for detection, and the optical probe 5 is used to receive the light and collect the absorbance signal.

[0052] The fluid control module includes a peristaltic metering pump 4, a reagent bottle 3, a volumetric cavity 7, a water inlet 9, a water outlet 11, a drain valve, and a stirring pump 6. The water inlet 9 is used to receive boiler water samples and transport them to the volumetric cavity 7. The water outlet 11 is used to discharge the rinsing liquid, reaction liquid, and cleaning waste liquid from the volumetric cavity 7. The drain valve is used to control the opening and closing of the water outlet 11. The reagent bottle 3 is used to store the chrome black T colorimetric reagent. The peristaltic metering pump 4 is used to quantitatively extract the colorimetric reagent from the reagent bottle 3 and inject it into the volumetric cavity 7 through the reagent inlet 8. The stirring pump 6 is used to stir the water sample and colorimetric reagent in the volumetric cavity 7 to ensure that they are fully mixed and reacted.

[0053] The touch control screen 2 has a built-in program that controls the equipment's operation: during operation, it controls the inlet 9 to take in water, and after the water sample enters the volume chamber 7, it is discharged through the outlet 11 for rinsing. After the set time is reached, it controls the drain valve to close. Then, it controls the peristaltic metering pump 4 to inject the colorimetric reagent in the reagent bottle 3 into the volume chamber 7 in a quantitative manner, and controls the stirring pump 6 to start stirring. At the same time, the program can receive signals collected by the optical probe 5 and the LED light source 10, analyze and detect the signals to obtain water hardness data, and display the water hardness data in real time on the touch control screen 2.

[0054] Integrating the functions of multiple components such as LED light source 10, optical probe 5, and peristaltic metering pump 4, it can complete the entire process from water intake at inlet 9, reaction in volumetric cavity 7, to water discharge at outlet 11 and data display on touch screen 2 without the need for additional equipment, simplifying deployment and operation, and adapting to the compact environment of industrial boiler sites.

[0055] Ensuring basic testing accuracy: By standardizing the processes of water inlet 9, quantitative injection by peristaltic metering pump 4, and thorough mixing by stirring pump 6, errors caused by poor coordination of dispersed components are avoided, laying the foundation for subsequent accuracy improvement and initially meeting the requirements for boiler water hardness testing.

[0056] Reduced operational complexity: The touch control screen 2 has a built-in program that automatically controls the operation of components such as the inlet 9, outlet 11, and peristaltic metering pump 4. Operators only need to view the data on the screen and do not need to operate manually, which reduces the professional skill requirements and human error.

[0057] In this embodiment, the early warning unit is linked with the built-in program of the touch control screen 2. When the water hardness data is unqualified, the early warning unit issues an early warning. The built-in program of the touch control screen 2 can also control the equipment to perform the start-up flushing process. When the equipment is turned on, it controls the inlet 9 to take in water and the outlet 11 to drain water, flushing the volume chamber 7 and the optical probe 5 to protect the optical probe 5. The data transmission unit is equipped with switch output and 4-20mA signal output functions and supports RS485 communication protocol. The switch output function can be used to cut off the boiler water inlet pipe when the early warning unit issues an early warning to ensure the safety of the boiler water quality. The compensation algorithm unit is used to correct the interference factors in the detection process and improve the detection accuracy.

[0058] When the warning unit is triggered, the data transmission unit quickly cuts off the inlet pipe 9 to prevent substandard water from entering the boiler, causing scaling and pipe bursts, thus improving operational safety and reducing economic losses. The start-up flushing process cleans the volumetric cavity 7 and the optical probe 5, preventing contamination and failure of the optical probe 5, extending its service life, and reducing replacement frequency and costs. The compensation algorithm unit corrects interference, making the signal collected by the optical probe 5 more accurate, and the data displayed on the touch control screen 2 more accurately reflects the water quality, providing a reliable basis for water treatment decisions. Multiple data transmission methods allow data to be integrated into the boiler's DCS system without additional adaptation, meeting the needs of different industrial scenarios for inlet pipe 9 control and water quality data monitoring.

[0059] Specifically, the LED light source 10 includes a main wavelength LED light source and a reference wavelength LED light source. The main wavelength LED light source has a wavelength of 520±5nm, and the reference wavelength LED light source has a wavelength of 700±10nm. The optical probe 5 integrates a high-sensitivity photodetector, which can receive the light from the main wavelength LED light source and the reference wavelength LED light source respectively, and collect the absorbance of the main wavelength LED light source. and reference wavelength absorbance .

[0060] The LED light source 10 features a dual-wavelength design combined with the optical probe 5 for signal acquisition. This effectively eliminates interference from suspended solids and air bubbles. Compared to a single wavelength, the detection error is reduced by more than 40% in complex water conditions such as high turbidity, improving accuracy and stability. The high-sensitivity detector of the optical probe 5 ensures that even weak signals from the LED light source 10 can be accurately acquired. Even in water with low hardness, clear signals can be obtained, expanding the detection range and meeting the requirements for low-hardness water.

[0061] Furthermore, the volumetric cavity 7 also integrates a constant-temperature reaction chamber and a PT1000 temperature sensor. The constant-temperature reaction chamber is used to control the temperature of the water sample and colorimetric reagent mixing reaction inside the volumetric cavity 7, with the controlled temperature at 50±0.5℃. The PT1000 temperature sensor is used to collect real-time temperature data inside the volumetric cavity 7. The compensation algorithm unit can call the temperature data collected by the PT1000 temperature sensor to dynamically correct the drift of the molar absorptivity ε value, and at the same time, it can adjust the absorbance based on the dominant wavelength. and reference wavelength absorbance Calculate the corrected absorbance to deduct interference from suspended matter.

[0062] The constant-temperature reaction chamber ensures consistent reaction conditions within volumetric cavity 7, avoiding reaction differences caused by temperature fluctuations and guaranteeing consistent baselines for each test, thus improving repeatability. The PT1000 temperature sensor, in conjunction with a compensation algorithm, ensures that the consistency error of the detection data is ≤±1.5% when the boiler water sample temperature fluctuates by 5-10℃, avoiding temperature errors common in traditional equipment and adapting to the unstable temperature environment of industrial sites. Through algorithmic correction of suspended solids interference, in water samples with turbidity of 20 NTU, the data collected by optical probe 5, after processing, has an error of ≤±2.3%, enhancing the equipment's adaptability to complex water quality conditions.

[0063] Furthermore, the self-cleaning module includes an ultrasonic transducer and a backwash flow path. The ultrasonic transducer is located around the optical probe 5 and is used to clean the optical probe 5 and the inner wall of the volumetric cavity 7. The backwash flow path is connected to the high-pressure air source and the sampling pipeline and is used to backwash the sampling pipeline through high-pressure air pulses. The touch control screen 2 has a built-in program that can control the self-cleaning module to start and clean the equipment regularly.

[0064] The ultrasonic transducer cleans the optical probe 5 and the volumetric cavity 7, while high-pressure backflushing cleans the sampling pipeline, extending the maintenance cycle from the traditional 1 month to over 6 months, reducing the frequency of manual maintenance and saving over 80% in labor costs annually. Non-contact cleaning avoids damage to the optical probe 5, and high-pressure backflushing protects the sampling pipeline, extending the lifespan of components such as the optical probe 5 by 1 to 3 years or more, reducing replacement costs. Regular cleaning prevents malfunctions and downtime caused by blockages in the volumetric cavity 7 and sampling pipeline, as well as contamination of the optical probe 5, improving operational reliability and reducing the risk of boiler water quality monitoring interruptions.

[0065] Furthermore, the sampling error of the peristaltic metering pump 4 is ≤±2%, and the amount of colorimetric reagent injected into the volumetric cavity 7 from the reagent bottle 3 in a single injection is controlled within a reasonable range to ensure that the water sample and the colorimetric reagent react fully and reduce reagent consumption; the volumetric cavity 7 is sealed to the optical probe 5 to prevent leakage of water sample or colorimetric reagent.

[0066] The peristaltic metering pump 4 precisely dispenses reagent, ensuring that the water sample and colorimetric reagent react in the optimal ratio within the volumetric chamber 7. This avoids insufficient dosage leading to low data or excessive dosage resulting in waste, improving detection accuracy and reducing reagent consumption costs. The sealed design of the volumetric chamber 7 and optical probe 5 prevents leakage of water sample and colorimetric reagent, which could corrode equipment components and contaminate the field environment, ensuring safe equipment operation and environmental cleanliness.

[0067] Furthermore, the built-in program on the touch control screen 2 can set the water inlet 9 water inlet duration, rinsing time, drain valve closing time, peristaltic metering pump 4 injection dosage and agitation pump 6 agitation time. It can also record historical detection data during equipment operation, including water hardness data, detection time and equipment operating status data. Historical detection data can be exported via RS485 communication protocol.

[0068] Adjustable parameters allow the equipment to adapt to different boiler water samples. For example, for high-turbidity water samples, the rinsing time at inlet 9 can be extended; for high-hardness water samples, the injection dosage of peristaltic metering pump 4 and the stirring time of agitator pump 6 can be adjusted, expanding the application range. Historical data storage and export functions facilitate tracing water quality change trends, analyzing boiler operating status, and developing water treatment plans. Simultaneously, operational data from components such as inlet 9 and peristaltic metering pump 4 can help predict faults and assist in equipment maintenance.

[0069] Furthermore, in addition to being equipped with switch output, 4-20mA signal output function and supporting RS485 communication protocol, the data transmission unit also supports Modbus protocol transmission, which can upload water hardness data to the boiler DCS system or external monitoring system. The data transmission rate is ≥9600bps and the data transmission error is ≤0.1%.

[0070] Multi-protocol transmission enables direct data access to the boiler DCS system and enterprise monitoring platform without the need for additional protocol conversion modules, reducing integration costs, avoiding conversion delay errors, and ensuring real-time control of the inlet pipe (9) and water quality monitoring. High-speed, low-error transmission allows remote terminals to obtain accurate data detected by the optical probe (5) and processed by the touch screen (2) in real time, enabling timely understanding of water quality conditions, rapid decision-making, and providing a reliable basis for subsequent data analysis.

[0071] This invention also provides an online method for detecting boiler water hardness, used in an online boiler water hardness detector based on Lambert-Beer's law, characterized by comprising the following steps:

[0072] S1: When the equipment is turned on, the built-in program on the touch control screen 2 starts the start-up flushing process, controls the water inlet 9 to open, and the boiler water sample enters the volume chamber 7. At the same time, controls the drain valve to open, and the liquid in the volume chamber 7 is discharged through the water outlet 11 to flush the volume chamber 7 and the optical probe 5. After the flushing is completed, it enters the standby state.

[0073] S2: During testing, the built-in program on the touch control screen 2 controls the inlet 9 to open, and the water sample enters the volume chamber 7. Then, the outlet 11 is controlled to discharge the water sample for rinsing. After the set rinsing time is reached, the drain valve is controlled to close.

[0074] S3: The built-in program of the touch control screen 2 controls the peristaltic metering pump 4 to start, quantitatively extracting the Chrome Black T colorimetric reagent from the reagent bottle 3 and injecting it into the volume chamber 7. Then, it controls the stirring pump 6 to start, stirring the water sample and colorimetric reagent in the volume chamber 7 to make them fully mixed and react.

[0075] S4: Activate LED light source 10, the light shines on the mixed liquid in volume chamber 7, the optical probe 5 receives the light transmitted through the mixed liquid, collects the absorbance signal and transmits it to the built-in program of touch control screen 2;

[0076] S5: The built-in program on the touch control screen 2 analyzes and detects the absorbance signal, and calculates the boiler water hardness value by combining the correction data from the compensation algorithm unit. The value is calculated in mg / L and displayed in real time on the touch control screen 2;

[0077] S6: The built-in program of the touch control screen 2 judges the water hardness value. If the water hardness value is not up to standard, the control warning unit issues a warning, and at the same time the data transmission unit cuts off the boiler water inlet pipe through the switch output function.

[0078] S7: After the test is completed, the built-in program on the touch control screen 2 controls the drain valve to open, and the reaction liquid in the volume chamber 7 is discharged through the outlet 11, completing one test process.

[0079] S8: The self-cleaning module is activated periodically via the built-in program on the touch control screen 2 to clean the optical probe 5, volume chamber 7, and sampling pipeline. At the same time, the equipment is calibrated periodically using a standard hardness solution to ensure detection accuracy.

[0080] Furthermore, in step S4, the LED light source 10 operates in a time-division multiplexing mode. First, the main wavelength LED light source is turned on, and the optical probe 5 collects the absorbance of the main wavelength. Then switch to the reference wavelength LED light source, and optical probe 5 collects the absorbance at the reference wavelength. In step S5, the built-in program on the touch control screen 2 calculates and corrects the absorbance. This is the turbidity correction factor, with a value ranging from 0.95 to 1.05, and is used to fit the equation based on the calibration curve. Calculate water hardness value, correlation coefficient The start-up rinsing process duration in step S1 and the rinsing time in step S2 can be set via the built-in program on the touch control screen 2, with a setting range of 1-5 minutes. In step S3, the mixing reaction temperature of the water sample and the color developer is controlled at 50±0.5℃, and the reaction time is controlled at 3-5 minutes. In step S8, the cleaning cycle of the self-cleaning module is set to 24 hours, the single cleaning time is 3-5 minutes, and the cleaning waste liquid is discharged through the outlet 11.

[0081] Finally, it should be noted that the electronic components in the control screen 2 and other components in this embodiment are all general standard parts or parts known to those skilled in the art. Their structure and principle can be known to those skilled in the art through technical manuals or conventional experimental methods. In the idle part of this device, all the above-mentioned electrical components are connected by wires. The specific connection method should refer to the working order between each electrical component in the above working principle to complete the electrical connection. All of these are technologies known in the art.

[0082] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. An online boiler water hardness detector based on Beer-Lambert's law, characterized in that: It includes an equipment housing, an optical module, a fluid control module, a self-cleaning module, a compensation algorithm unit, a data transmission unit, a touch control screen (2), and an early warning unit; The optical module includes an LED light source (10) and an optical probe (5). The LED light source (10) is used to provide the light required for detection, and the optical probe (5) is used to receive the light and collect the absorbance signal. The fluid control module includes a peristaltic metering pump (4), a reagent bottle (3), a volumetric cavity (7), a water inlet (9), a water outlet (11), a drain valve, and a stirring pump (6). The water inlet (9) is used to receive boiler water samples and transport the water samples to the volumetric cavity (7). The water outlet (11) is used to discharge the rinsing liquid, reaction liquid, and cleaning waste liquid in the volumetric cavity (7). The drain valve is used to control the opening and closing of the water outlet (11). The reagent bottle (3) is used to store chrome black T color reagent. The peristaltic metering pump (4) is used to quantitatively extract the color reagent in the reagent bottle (3) and inject it into the volumetric cavity (7) from the reagent inlet (8). The stirring pump (6) is used to stir the water sample and color reagent in the volumetric cavity (7) to make them fully mixed and react. The touch screen (2) has a built-in program that controls the equipment operation process: during operation, the inlet (9) is controlled to take in water, and after the water sample enters the volume chamber (7), it is discharged through the outlet (11) for rinsing. After the set time is reached, the drain valve is controlled to close. Then, the peristaltic metering pump (4) is controlled to inject the colorimetric reagent in the reagent bottle (3) into the volume chamber (7) in a quantitative manner, and the stirring pump (6) is controlled to start stirring. At the same time, the program can receive the signals collected by the optical probe (5) and the LED light source (10), analyze and detect the signals to obtain water hardness data, and display the water hardness data in real time on the touch screen (2).

2. The online boiler water hardness detector based on Beer-Lambert law according to claim 1, characterized in that: The warning unit is linked with the built-in program of the touch control screen (2). When the water hardness data is not up to standard, the warning unit issues a warning. The built-in program of the touch control screen (2) can also control the equipment to perform the start-up flushing process. When the equipment is started, it controls the inlet (9) to take in water and the outlet (11) to drain water to flush the volume chamber (7) and the optical probe (5) to protect the optical probe (5). The data transmission unit is equipped with switch output and 4-20mA signal output functions and supports RS485 communication protocol. The switch output function can be used to cut off the boiler water inlet pipe when the warning unit issues a warning to ensure the safety of the boiler water quality. The compensation algorithm unit is used to correct the interference factors in the detection process and improve the detection accuracy.

3. The online boiler water hardness detector based on Beer-Lambert law according to claim 1, characterized in that: The LED light source (10) includes a main wavelength LED light source and a reference wavelength LED light source. The main wavelength LED light source has a wavelength of 520±5nm, and the reference wavelength LED light source has a wavelength of 700±10nm. The optical probe (5) integrates a high-sensitivity photodetector, which can receive the light from the main wavelength LED light source and the reference wavelength LED light source respectively, and collect the absorbance of the main wavelength LED light source. and reference wavelength absorbance .

4. The online boiler water hardness detector based on Beer-Lambert law according to claim 1, characterized in that: The volumetric cavity (7) also integrates a constant temperature reaction chamber and a PT1000 temperature sensor. The constant temperature reaction chamber is used to control the temperature of the water sample and colorimetric reagent mixing reaction inside the volumetric cavity (7), and the controlled temperature is 50±0.5℃. The PT1000 temperature sensor is used to collect real-time temperature data inside the volumetric cavity (7). The compensation algorithm unit can call the temperature data collected by the PT1000 temperature sensor to dynamically correct the drift of the molar absorptivity ε value, and at the same time, it can adjust the absorbance based on the main wavelength. and reference wavelength absorbance Calculate the corrected absorbance to deduct interference from suspended matter.

5. The online boiler water hardness detector based on Beer-Lambert law according to claim 1, characterized in that: The self-cleaning module includes an ultrasonic transducer and a backwash flow path. The ultrasonic transducer is located around the optical probe (5) and is used to clean the optical probe (5) and the inner wall of the volume cavity (7). The backwash flow path is connected to the high-pressure air source and the sampling pipeline and is used to backwash the sampling pipeline through high-pressure air pulses. The touch screen (2) has a built-in program that can control the self-cleaning module to start and clean the equipment regularly.

6. The online boiler water hardness detector based on Beer-Lambert law according to claim 1, characterized in that: The sampling error of the peristaltic metering pump (4) is ≤±2%. The amount of color reagent injected into the volume chamber (7) from the reagent bottle (3) in a single operation is controlled within a reasonable range to ensure that the water sample and the color reagent react fully and reduce reagent consumption. The volume chamber (7) is sealed to the optical probe (5) to prevent leakage of water sample or color reagent.

7. The online boiler water hardness detector based on Beer-Lambert law according to claim 1, characterized in that: The built-in program of the touch control screen (2) can set the water inlet time (9), flushing time, drain valve closing time, peristaltic metering pump (4) injection dosage and stirring pump (6) stirring time. At the same time, it can record historical detection data during equipment operation, including water hardness data, detection time and equipment operation status data. Historical detection data can be exported through RS485 communication protocol.

8. The online boiler water hardness detector based on Beer-Lambert law according to claim 1, characterized in that: In addition to being configured with switch output, 4-20mA signal output function and support for RS485 communication protocol, the data transmission unit also supports Modbus protocol transmission, which can upload water hardness data to the boiler DCS system or external monitoring system. The data transmission rate is ≥9600bps and the data transmission error is ≤0.1%.

9. A method for online detection of boiler water hardness, used in the online boiler water hardness detector based on Lambert-Beer's law as described in any one of claims 1-8, characterized in that, Includes the following steps: S1: The device is turned on. The built-in program of the touch control screen (2) starts the start-up flushing process, controls the water inlet (9) to open, and the boiler water sample enters the volume chamber (7). At the same time, the drain valve is opened, and the liquid in the volume chamber (7) is discharged through the water outlet (11) to flush the volume chamber (7) and the optical probe (5). After the flushing is completed, it enters the standby state. S2: During testing, the built-in program of the touch control screen (2) controls the water inlet (9) to open, and the water sample enters the volume chamber (7). Then, the water outlet (11) is controlled to discharge the water sample for rinsing. After the set rinsing time is reached, the drain valve is controlled to close. S3: The built-in program of the touch control screen (2) controls the peristaltic metering pump (4) to start, quantitatively extract the chrome black T color reagent in the reagent bottle (3) and inject it into the volume chamber (7), and then controls the stirring pump (6) to start, stirring the water sample and color reagent in the volume chamber (7) to make them fully mixed and react; S4: Activate the LED light source (10), and the light shines on the mixed liquid in the volume chamber (7). The optical probe (5) receives the light transmitted through the mixed liquid, collects the absorbance signal, and transmits it to the built-in program of the touch control screen (2). S5: The touch screen (2) has a built-in program that analyzes and detects the absorbance signal, and calculates the boiler water hardness value by combining the correction data from the compensation algorithm unit. The value is calculated in mg / L and displayed in real time on the touch control screen (2); S6: The built-in program of the touch control screen (2) judges the water hardness value. If the water hardness value is not qualified, the control warning unit issues a warning, and at the same time the data transmission unit cuts off the boiler water inlet pipe through the switch output function. S7: After the test is completed, the built-in program of the touch control screen (2) controls the drain valve to open, and the reaction liquid in the volume chamber (7) is discharged through the outlet (11) to complete one test process; S8: The self-cleaning module is activated periodically via the built-in program on the touch control screen (2) to clean the optical probe (5), volume chamber (7) and sampling pipeline. At the same time, the equipment is calibrated periodically using a standard hardness solution to ensure detection accuracy.

10. The online detection method for boiler water hardness according to claim 9, characterized in that, In step S4, the LED light source (10) operates in a time-division multiplexing mode. First, the main wavelength LED light source is turned on, and the optical probe (5) collects the absorbance of the main wavelength. ; Then switch to the reference wavelength LED light source, and the optical probe (5) collects the absorbance at the reference wavelength. In step S5, the built-in program of the touch control screen (2) calculates and corrects the absorbance. k is the turbidity correction coefficient, ranging from 0.95 to 1.05, and the equation is fitted according to the calibration curve. Calculate water hardness value, correlation coefficient The start-up flushing process duration in step S1 and the flushing time in step S2 can be set by the built-in program on the touch control screen (2), with a setting range of 1-5 minutes; in step S3, the mixing reaction temperature of the water sample and the color developer is controlled at 50±0.5℃, and the reaction time is controlled at 3-5 minutes; in step S8, the cleaning cycle of the self-cleaning module is set to 24 hours, the single cleaning time is 3-5 minutes, and the cleaning waste liquid is discharged through the outlet (11).

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