A hydrogen sulfide hot spring immersion bath parameter optimization system and method

Abstract

The application discloses a hydrogen sulfide hot spring bathing parameter optimization method and system, and belongs to the technical field of automatic control. The method comprises the following steps: constructing a multi-source perception array composed of a water quality monitoring unit, an environment monitoring unit and a physiological sign monitoring unit, collecting multi-dimensional parameters such as dissolved hydrogen sulfide concentration, hydrogen ion concentration index, water temperature, air hydrogen sulfide concentration, heart rate and blood oxygen saturation through an edge computing gateway in real time; establishing a hydrogen sulfide gas-liquid equilibrium nonlinear dynamics model to calculate the proportion of molecular hydrogen sulfide and the escape rate; constructing a bathing safety and curative effect evaluation system based on physiological feedback, and defining a safety risk index and a curative effect weight factor. The application realizes closed-loop precise regulation and control of the hydrogen sulfide hot spring bathing process, and significantly improves the stability of effective components under the premise of ensuring the safety of bathers.

Description

Technical Field

[0001] This invention relates to the field of automatic control technology, specifically to a system and method for optimizing parameters of hydrogen sulfide hot spring bathing. Background Technology

[0002] Hydrogen sulfide hot springs, as a typical chemical mineral spring, are rich in dissolved hydrogen sulfide gas and sulfide ions that can be absorbed through the skin and enter the human microcirculation, thereby playing a positive role in dilating blood vessels, regulating the feedback of the nervous system, and anti-inflammatory and analgesic effects.

[0003] Hydrogen sulfide in aqueous solution is not only highly volatile, but its dissociation equilibrium also exhibits a strong nonlinear coupling correlation with water temperature, environmental pressure, and especially the hydrogen ion concentration (pH value) of the water. Even slight physical disturbances or environmental fluctuations can lead to a sudden decrease in the effective hydrogen sulfide concentration in the water or a momentary surge in the hydrogen sulfide content in the air. Existing formulation technologies often focus only on initial parameter settings, completely neglecting the dynamic interference of human sweat and sebum metabolites on the pH value of the water during bathing, as well as the impact of flow field fluctuations caused by bathing movements on the gas escape rate. Consequently, in practical applications, even with a scientifically formulated initial recipe, the stability of the active ingredients rapidly deteriorates as the bathing process continues, leading to significant and uncontrollable fluctuations in therapeutic efficacy.

[0004] Because hydrogen sulfide is highly biotoxic, the concentration range in which it exerts its therapeutic effect and the safe threshold range for causing poisoning are exceptionally narrow. Most existing physical regulation devices fall under the category of open-loop control, with their regulation logic based on preset empirical parameters, lacking real-time mapping analysis between the spatial flow field, real-time air quality, and water physicochemical indicators within the bathroom. In the relatively enclosed bathing space, if intelligent dynamic compensation cannot be made based on the user's immediate physiological feedback, indoor temperature and humidity fluctuations, and airflow exchange efficiency, hydrogen sulfide can easily accumulate indoors, leading to safety risks, or the therapeutic effect may be rendered ineffective due to insufficient concentration maintenance. This systematic deviation arising from the coupling of complex variables is a theoretical bottleneck that cannot be overcome by relying on a single physical device structural design or simple initial component ratios.

[0005] How to propose an intelligent optimization scheme that can maximize safety, stability and efficacy while addressing the inherent technical contradictions of hydrogen sulfide, such as its high volatility, environmental sensitivity and extremely narrow safety window, has become an urgent need for those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a method and system for optimizing parameters in hydrogen sulfide hot spring bathing, which solves the technical problem that the lack of multi-dimensional dynamic mapping and closed-loop control of water quality, environment and physiological parameters in the existing hydrogen sulfide hot spring bathing process leads to poor stability of effective components and an inability to balance therapeutic effects and safety.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0008] A method for optimizing parameters of hydrogen sulfide hot spring bathing includes the following steps:

[0009] Step 1: Construct a real-time data acquisition field based on a multi-source sensing array. A sensor network consisting of a water quality monitoring unit, an environmental monitoring unit, and a physiological characteristic monitoring unit is deployed within the bathing space. The water quality monitoring unit collects real-time data on dissolved hydrogen sulfide concentration, hydrogen ion concentration index, water temperature, redox potential, and conductivity in the bathing water. The environmental monitoring unit collects real-time data on air hydrogen sulfide concentration, ambient temperature, relative humidity, and wind speed at the breathing zone height within the bathing space. The physiological characteristic monitoring unit acquires real-time heart rate, blood oxygen saturation, predicted core body temperature, and skin surface electrical signals of the bather using wearable biosensors. All collected data is transmitted via fieldbus to an edge computing gateway for synchronization and preprocessing.

[0010] Step 2: Establish a nonlinear dynamic model for hydrogen sulfide gas-liquid equilibrium: Using the water quality parameters obtained in Step 1, calculate the real-time proportion of molecular hydrogen sulfide in the water; based on the second-order dissociation constant of hydrogen sulfide in aqueous solution, calculate the Henry coefficient at the current water temperature using the Henry's law correction formula, and derive the theoretical equilibrium partial pressure of hydrogen sulfide on the water surface; by introducing the wind speed in the spatial flow field as a disturbance factor, construct an escape rate model and calculate the mass flow rate of hydrogen sulfide escaping from the liquid phase to the gas phase per unit time.

[0011] Step 3: Construct a safety and efficacy evaluation system for immersion bathing based on physiological feedback: Define an efficacy weighting factor, which is positively correlated with the concentration of molecular hydrogen sulfide and water temperature; define a safety risk index, which is a function of the cumulative exposure dose of hydrogen sulfide in the air and the deviation of the bather's physiological parameters from the baseline value; when the safety risk index exceeds a preset first safety threshold, the system activates a safety priority mode; when the safety risk index is lower than the first safety threshold and the efficacy weighting factor is lower than the expected efficacy threshold, the system activates an efficacy optimization mode.

[0012] Step 4: Perform multivariate coupled bath parameter decision-making and dynamic compensation: Based on the model predictive control algorithm, with the constraints of maintaining a constant concentration of molecular hydrogen sulfide in the water and ensuring that the concentration of hydrogen sulfide in the air does not exceed the standard, calculate the required dynamic compensation amount; the compensation methods include at least one or a combination of dynamic pH adjustment, precise solubility control, spatial concentration control and feeding logic.

[0013] Furthermore, in step two, the molar fraction of molecular hydrogen sulfide among all dissolved hydrogen sulfide is determined in the following way:

[0014] Based on the real-time collected hydrogen ion concentration index, the first-order dissociation constant and the second-order dissociation constant of hydrogen sulfide, the results are calculated according to the second-order dissociation equilibrium of hydrogen sulfide. The first-order dissociation constant is linearly related to the water temperature and decreases as the water temperature increases. The second-order dissociation constant is 12.1 at 25°C, or is linearly related to the water temperature.

[0015] Furthermore, in step two, the Henry coefficient at the current water temperature is determined by an exponential function relationship based on the Henry coefficient at the reference temperature and the temperature coefficient.

[0016] Based on the Henry coefficient and the molar concentration of liquid molecular hydrogen sulfide, the theoretical equilibrium partial pressure of hydrogen sulfide on the water surface is determined.

[0017] The escape rate model is based on the two-film theory. The mass flow rate of hydrogen sulfide escaping from the liquid phase to the gas phase per unit time is determined by the liquid phase mass transfer coefficient, the gas-liquid contact area, and the difference between the molecular hydrogen sulfide molar concentration in the liquid phase and the interfacial equilibrium concentration.

[0018] The liquid phase mass transfer coefficient is related to the wind speed in the spatial flow field and is determined by an empirical formula.

[0019] Furthermore, in step two, a correction factor based on the rate of change of redox potential is introduced to correct the hydrogen sulfide mass flow rate in real time; the correction factor is linearly related to the rate of change of redox potential and is weighted by correction coefficients; the corrected hydrogen sulfide mass flow rate is the product of the correction factor and the uncorrected hydrogen sulfide mass flow rate.

[0020] Furthermore, in step three, the therapeutic effect weighting factor is determined based on the ratio of molecular hydrogen sulfide concentration to target concentration and the ratio of water temperature to reference temperature.

[0021] The safety risk index is determined by a weighted sum of the ratio of cumulative exposure dose to safe threshold dose of hydrogen sulfide in the air, the ratio of heart rate variability to baseline heart rate, and the ratio of blood oxygen saturation variability to baseline blood oxygen saturation.

[0022] Wherein, the cumulative exposure dose is the integral of the air hydrogen sulfide concentration over time from the start of the bath to the current moment, the heart rate change rate is the absolute value of the difference between the real-time heart rate and the baseline heart rate at rest before the bath, the blood oxygen saturation change rate is the absolute value of the difference between the baseline blood oxygen saturation at rest before the bath and the real-time blood oxygen saturation; and the sum of the weighting coefficients of the weighted sum is 1.

[0023] Furthermore, in step four, the dynamic adjustment of pH value adopts a graded PID control strategy:

[0024] The first level is predictive control, which estimates the acid and alkali consumption based on the water replenishment flow rate and the preset hydrogen sulfide concentration.

[0025] The second stage is feedback control, which performs closed-loop correction based on the real-time collected hydrogen ion concentration index; the dosing point is set at the Venturi jet mixer after the circulating pump.

[0026] Furthermore, in step four, spatial concentration control is achieved through linkage with the variable frequency fresh air system:

[0027] The exhaust volume is dynamically adjusted according to the slope of the increase in air hydrogen sulfide concentration to ensure that the hydrogen sulfide concentration in the breathing zone is always below 10 mg / m³.

[0028] The variable frequency fresh air system adopts a gradient control algorithm based on spatial concentration. According to the concentration difference at different points provided by the sensor array, the edge computing gateway calculates the centroid of pollutant diffusion in the immersion space. By adjusting the speed of the variable frequency fan in different directions, a directional airflow organization is formed.

[0029] Furthermore, in step one, the water quality monitoring unit uses a pollution-resistant gold electrode hydrogen sulfide sensor with a response time T90 of less than 30 seconds, a measurement range of 0-100 mg / L, and a resolution of not less than 0.1 mg / L; the physiological signs monitoring unit uses a flexible fabric electrode and collects pulse rate data using photoplethysmography through sensing contacts integrated into the inner wall of the bathtub or a wearable waterproof module.

[0030] Furthermore, in step three, when the heart rate change rate exceeds 30% of the initial baseline or the blood oxygen saturation drops by more than 3%, it is determined to be physiological overload, and the highest level of fresh air exchange is forcibly activated and an audible and visual warning is issued.

[0031] Furthermore, the control decision module in step four adopts an optimization framework that combines a concentration prediction algorithm based on a long short-term memory network (LSTM) with a multi-objective genetic algorithm (NSGA-II). The LSTM network is used to predict the trend of dissolved hydrogen sulfide concentration and air hydrogen sulfide concentration in the next 5 minutes, and the NSGA-II algorithm is used to search for the optimal combination of execution instructions.

[0032] Furthermore, the LSTM network is a three-layer stacked structure, with each layer containing 128 hidden units. The input is multi-dimensional sensor historical data from the past 15 minutes, and the output is a concentration prediction sequence for the next 5 minutes. The NSGA-II algorithm has a population size of 100, 200 iterations, a crossover probability of 0.9, a mutation probability of 0.1, and optimization objectives include concentration deviation integral, air concentration exceedance risk integral, and energy consumption integral.

[0033] Furthermore, in step two, the introduced correction terms include a conductivity correction factor and a redox potential correction factor; the conductivity correction factor is linearly related to the rate of change of conductivity and is weighted by a sweat dilution calibration coefficient; the redox potential correction factor is linearly related to the absolute value of the rate of change of redox potential and is weighted by an oxidation compensation calibration coefficient; the comprehensive correction factor is the product of the conductivity correction factor and the redox potential correction factor; the corrected hydrogen sulfide mass flow rate is the product of the comprehensive correction factor and the uncorrected hydrogen sulfide mass flow rate.

[0034] Furthermore, the gradient control algorithm based on spatial concentration includes:

[0035] The concentration of hydrogen sulfide in the air is monitored in real time by using air hydrogen sulfide sensors placed at multiple points in the immersion space. The concentration gradient and concentration-weighted centroid in the horizontal direction are calculated. The speed of each exhaust fan is dynamically adjusted according to the position of the centroid so that the exhaust volume is concentrated on the pollution source area. At the same time, the fresh air supply fan is controlled to maintain a slight negative pressure to form a directional airflow.

[0036] In addition, the present invention also discloses a hydrogen sulfide hot spring bathing parameter optimization system applying the method described above, the system comprising a sensing layer, a logic control layer, and an execution layer:

[0037] The sensing layer includes:

[0038] The integrated water quality sensor group installed on the circulating return water pipeline of the bathing pool is used to detect dissolved hydrogen sulfide concentration, hydrogen ion concentration index, water temperature and redox potential.

[0039] An array of air quality sensors, distributed on the walls of the bathing pool and at a height of 30 cm above the head of the bather, is used to detect the concentration of hydrogen sulfide in the air, wind speed, and relative humidity.

[0040] A waterproof biosensor module is placed on the surface of the bather's skin to monitor physiological signs;

[0041] The logical control layer includes an edge computing gateway, which integrates a data acquisition module, a parameter analysis module, a gas-liquid balance modeling module, and a control decision module. The parameter analysis module is responsible for denoising and feature extraction of the data from the perception layer. The control decision module generates control commands for the execution layer based on a preset multi-objective optimization algorithm.

[0042] The execution layer includes:

[0043] The replenishment unit includes a hydrogen sulfide concentrate storage tank, a precision proportioning pump, and an electromagnetic flow meter;

[0044] pH adjustment unit, including acid / alkali reagent tank, metering pump and jet mixer;

[0045] Temperature control unit, including electric proportional regulating valve and plate heat exchanger;

[0046] The environmental control unit includes a variable frequency exhaust fan, a fresh air supply fan, and automatic louvers.

[0047] Furthermore, the logic control layer also includes a safety redundancy module; the safety redundancy module adopts a hardwired connection logic independent of the main controller. When the concentration of hydrogen sulfide in the air reaches 20 mg / m³ or the emergency stop button is triggered, the safety redundancy module bypasses the algorithm control, directly and forcibly cuts off the liquid replenishment power supply, fully opens the exhaust system, and opens the drain valve to discharge the hot spring water in the pool.

[0048] Furthermore, the system also includes a cloud data storage and remote monitoring interface, which supports uploading the immersion parameter curves of each session to the database for building a long-term rehabilitation efficacy analysis model.

[0049] Furthermore, the internal structure of the jet mixer of the replenishment unit adopts a spiral guide vane design, which enables the injected hydrogen sulfide gas or concentrated liquid to form a strong vortex in the pipeline.

[0050] Furthermore, the integrated water quality sensor array includes a pollution-resistant gold electrode hydrogen sulfide sensor, a composite pH electrode, a platinum electrode redox potentiometer, a four-electrode conductivity sensor, and a PT1000 temperature sensor; the air quality sensor array includes an electrochemical air hydrogen sulfide sensor, an ultrasonic anemometer, and a capacitive humidity sensor.

[0051] Furthermore, the waterproof biosensor module transmits data to the edge computing gateway via Bluetooth Low Energy protocol or Sub-1GHz radio frequency; the outer shell of the waterproof biosensor module is encapsulated with medical-grade biocompatible fluororubber, achieving a waterproof rating of IP68.

[0052] Furthermore, the parameter analysis module inside the edge computing gateway uses a Kalman filter algorithm to denoise the raw sensor data.

[0053] Furthermore, the water quality monitoring unit adopts a combination of in-situ measurement and circulation pipeline measurement; redundant temperature and pH sensors are arranged at the inlet at the bottom of the bathing pool and the outlet on the pool wall, respectively, and the distribution gradient of parameters in the pool is obtained through differential calculation.

[0054] Furthermore, the dosing point of the pH adjustment unit is located at the Venturi jet mixer after the circulation pump, and the Venturi jet mixer has a spiral guide vane structure inside.

[0055] Furthermore, in the environmental control unit, a slight negative pressure gradient is maintained between the variable frequency exhaust fan and the fresh air supply fan, and the negative pressure gradient is 5-10 Pa.

[0056] Furthermore, the control decision module integrates an LSTM prediction unit and an NSGA-II optimization unit. The LSTM prediction unit takes 15 minutes of historical multidimensional data as input and outputs a concentration prediction for the next 5 minutes. The NSGA-II optimization unit uses the prediction as a basis to solve a multi-objective optimization problem and generate execution instructions.

[0057] Furthermore, the air quality sensor array includes at least four sensors distributed in different corners. The edge computing gateway calculates the concentration gradient and pollution centroid based on the concentration values ​​of each sensor, and independently adjusts the frequency of each exhaust fan according to the centroid position to achieve directional airflow organization.

[0058] Compared with the prior art, the present invention has the following beneficial effects:

[0059] This invention achieves precise quantitative compensation for volatile active components by establishing a nonlinear kinetic model of hydrogen sulfide gas-liquid equilibrium based on hydrogen ion concentration index and water temperature correction. Compared to the static adjustment method in traditional technologies that relies solely on initial parameter settings, this invention can respond in real time to changes in the flow field caused by the bather's limb movements and water surface fluctuations, as well as dynamic fluctuations in water quality physicochemical parameters caused by the accumulation of sweat and sebum metabolites. This ensures that the concentration of molecular hydrogen sulfide with therapeutic value in the water is consistently maintained within the medical dosage window. By calculating the proportion of molecular hydrogen sulfide in real time and dynamically predicting the dissipation rate, the loss trend of active components can be predicted in advance and compensated for, significantly improving the component stability and medical rehabilitation efficacy of hydrogen sulfide hot spring therapy.

[0060] This invention uses physiological indicators such as the bather's heart rate and blood oxygen saturation as the highest priority constraints in closed-loop control, effectively solving the technical challenge of a narrow safety window in hydrogen sulfide hot springs. By constructing a composite safety risk index that includes the cumulative exposure dose of hydrogen sulfide in the air and the degree of deviation of physiological parameters, the system can automatically adjust the bathing intensity or environmental ventilation based on the differences in physiological tolerance among individuals. When the rate of change in heart rate or the decrease in blood oxygen saturation exceeds the individualized baseline threshold, the system immediately determines it as physiological overload and activates the highest level of safety protection, fundamentally eliminating the safety hazard of hydrogen sulfide accumulation leading to poisoning, and achieving a technological leap from single environmental safety to dual human-environment safety protection.

[0061] This invention organically integrates dynamic pH adjustment, precise solubility control, dynamic component replenishment, and environmental spatial concentration management into a unified closed-loop control system. Through model predictive control algorithms within the edge computing gateway, the system can collaboratively schedule multiple actuators to maximize therapeutic efficacy while meeting safety constraints. Specifically, pH adjustment employs a hierarchical PID control strategy, with the dosing point located at the Venturi jet mixer to ensure molecular-level uniform mixing of the chemicals before they enter the bath. Spatial concentration management utilizes gradient-based directional airflow organization, dynamically adjusting the fan speeds in all directions based on the location of the pollutant diffusion centroid to create a micro-negative pressure field that guides the directional flow of escaping gases. This comprehensive collaborative optimization mechanism not only reduces ineffective waste of chemicals and energy but also achieves intelligent regulation of the bathing environment's microclimate, providing complete technical support for the transformation of hydrogen sulfide hot springs from traditional extensive utilization to precision medical applications.

[0062] This invention solves the technical problem in existing hydrogen sulfide hot spring bathing processes that, due to the lack of multi-dimensional dynamic mapping and closed-loop control of water quality, environment, and physiological parameters, the effective components are unstable and cannot achieve both therapeutic effects and safety. Attached Figure Description

[0063] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0064] Figure 1 This is an overall flowchart of the method described in this invention.

[0065] Figure 2 The flowchart for real-time data acquisition of the multi-source sensing array described in the invention is shown.

[0066] Figure 3This is one of the operating interfaces of the system described in the invention.

[0067] Figure 4 This is the second type of system operation interface described in the invention.

[0068] Figure 5 This is the third type of system operation interface described in the invention.

[0069] Figure 6 The fourth type of system operation interface described in the invention. Detailed Implementation

[0070] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the embodiments of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0071] The following is in conjunction with the appendix Figures 1-6 The embodiments of the present invention will be described in detail below.

[0072] This invention discloses a method for optimizing parameters of hydrogen sulfide hot spring bathing, as detailed below:

[0073] Step 1: Construct a real-time data acquisition field based on a multi-source sensing array.

[0074] A high-frequency, high-precision sensor network enables comprehensive digital characterization of the water-air-human three-phase coupled system. In the physical layout of the bathing space, the water quality monitoring unit is integrated into the return water pipeline and key points on the bottom of the bath. The core component is a fouling-resistant gold electrode hydrogen sulfide sensor. The sensor surface is covered with a selectively permeable fluoropolymer film, effectively blocking large molecular organic matter and mineral deposits from the hot spring water from contaminating the electrode surface and ensuring its response time. It maintains an extremely high level of sensitivity within 30 seconds, with a range of 0-100 mg / L and a resolution of 0.1 mg / L, enabling it to keenly detect minute fluctuations in hydrogen sulfide concentration.

[0075] Meanwhile, the water quality monitoring unit also integrates a composite pH electrode, a platinum electrode ORP meter, a four-electrode conductivity sensor, and a high-precision PT1000 temperature sensor. All these sensors are IP68 rated and their signals are aggregated in real time via the RS485 bus protocol.

[0076] In terms of environmental monitoring, this invention establishes a spatial gradient monitoring array within the bathing space; multiple electrochemical hydrogen sulfide sensors are deployed at various points in the vertical space at the height of the bather's breathing zone, approximately 30 cm to 50 cm above the water surface. These sensors, in conjunction with an ultrasonic anemometer and a capacitive humidity sensor, delineate the diffusion profile of hydrogen sulfide gas within the bathing space in real time.

[0077] This invention employs a wearable module based on flexible fabric electrodes. This module utilizes the photoplethysmography (PPG) principle, emitting 525 nm wavelength green light that penetrates the skin's capillaries. A highly sensitive photodiode receives the reflected light, thereby extracting the heart rate. and blood oxygen saturation Signal. Due to the high temperature and humidity characteristics of the hydrogen sulfide hot spring environment, the housing of the sensing module is made of biocompatible fluororubber material and undergoes a secondary injection molding process to ensure long-term operational stability at 42℃ and 95% relative humidity. All sensing layer data is synchronized and preprocessed through an edge computing gateway, with the sampling frequency strictly locked at 1 Hz, providing a highly timely raw sequence for subsequent algorithm processing.

[0078] Step 2: Establish a nonlinear dynamic model of hydrogen sulfide gas-liquid equilibrium.

[0079] The thermodynamic formulas were used to analyze the actual forms of hydrogen sulfide in water. In hydrogen sulfide hot spring water, sulfur exists in the molecular state of hydrogen sulfide (…). ), hydrogen sulfide ions ( ) and sulfide ions ( Hydrogen sulfide exists in three dynamic forms, but the molecular form is the one that has medical rehabilitation value and is easy to escape into the gas phase.

[0080] This invention utilizes real-time acquired pH and water temperature data. Calculate the proportion of molecular hydrogen sulfide. Its calculation logic is strictly based on the second-order dissociation equilibrium of hydrogen sulfide, and the formula is:

[0081] ;

[0082] in, The mole fraction of molecular hydrogen sulfide is dimensionless. This is the hydrogen ion concentration index, which is dimensionless. It is the first-order dissociation constant, dimensionless; It is the second-order dissociation constant, which is dimensionless.

[0083] Since water temperature has a significant impact on the dissociation constant, a temperature compensation coefficient is introduced, namely:

[0084] ;

[0085] ;

[0086] in, Water temperature, in °C.

[0087] As water temperature increases, the first-order dissociation constant decreases, meaning that under the same pH conditions, the proportion of molecular hydrogen sulfide will shift nonlinearly.

[0088] To further quantify the rate at which hydrogen sulfide escapes into the air, a modified Henry's Law formula was introduced.

[0089] Henry's coefficient calculated based on the current water temperature Based on the water surface concentration, the theoretical equilibrium partial pressure at the gas-liquid interface was calculated. :

[0090] ;

[0091] ;

[0092] in, Water temperature Henry's coefficient at time, unit is ; The Henry's law constant for hydrogen sulfide at 25°C (298 K) is given by a value of [value missing]. ; This is the temperature coefficient, with a value of 2000 K; Temperature is the thermodynamic temperature, and its unit is K. This represents the theoretical equilibrium partial pressure of hydrogen sulfide gas at the water surface, expressed in Pa. This represents the molar concentration of liquid molecular hydrogen sulfide, expressed in mol / L.

[0093] Furthermore, considering the dynamic disturbances in the immersion environment, the spatial flow field wind speed collected by the environmental monitoring unit... This is introduced as a key perturbation factor in the escape rate model. By calculating the mass transfer coefficient of the water surface boundary layer, the mass flow rate of hydrogen sulfide escaping from the liquid phase to the gas phase per unit time is obtained. :

[0094] ;

[0095] in, The mass flow rate of hydrogen sulfide escaping from the liquid phase to the gas phase per unit time is expressed in mg / s. is the liquid phase mass transfer coefficient, with units of m / s; This represents the gas-liquid contact area, measured in m². This represents the molar concentration of liquid molecular hydrogen sulfide, expressed in mol / L. This represents the concentration of the liquid phase at the gas-liquid interface in equilibrium with the gas phase, expressed in mol / L, and can be approximately determined using Henry's Law. With wind speed The relationship can be represented as:

[0096] ;

[0097] in, , These are empirical constants, calibrated experimentally. The velocity is the airflow velocity in the space, expressed in m / s.

[0098] To improve the robustness of the model, a factor derived from conductivity was also introduced. and redox potential The modified terms constitute Through calculation The rate of change of sulfur ions can be used to identify the trend of oxidation of sulfur ions by dissolved oxygen in water, thereby enabling the determination of the oxidation rate of sulfur ions by dissolved oxygen in water. Perform secondary calibration:

[0099] ;

[0100] in, The comprehensive correction factor is dimensionless. The correction factor is determined experimentally and its unit is s / mV; The rate of change of redox potential is expressed in mV / s. Redox potential, in mV. Corrected dissipation. This enables the system to overcome the lag in traditional chemical analysis and achieve instantaneous prediction of hydrogen sulfide content.

[0101] The third step is to construct a safety and efficacy evaluation system for immersion baths based on physiological feedback.

[0102] Human physiological response is used as the highest closed-loop constraint of the system. Therapeutic efficacy weighting factors are defined. This factor is positively correlated with the concentration of molecular hydrogen sulfide and water temperature, reflecting the potential effectiveness of the current environment for the body's osmotic absorption:

[0103] ;

[0104] in, This is a dimensionless weighting factor for therapeutic efficacy. This represents the concentration of molecular hydrogen sulfide, in mg / L. The target molecular state concentration, for example, 50 mg / L; Water temperature, in °C; For reference temperature, e.g., 40 ℃.

[0105] At the same time, the security risk index is calculated in real time. The exponent is a composite function, and its logical expression is:

[0106] ;

[0107] in:

[0108] This is a dimensionless safety risk index.

[0109] From the start of the bath to the present moment The cumulative exposure dose, expressed in mg·min / m³; for The concentration of hydrogen sulfide in the air at any given time, expressed in mg / m³.

[0110] The safe threshold dose is expressed in mg·min / m³.

[0111] , For real-time heart rate, The baseline heart rate values ​​were collected from the bather at rest 3 minutes before bathing, and all units are bpm.

[0112] , Real-time blood oxygen saturation;

[0113] The baseline blood oxygen saturation value is measured by the subject at rest 3 minutes before bathing, and all values ​​are in percent (%). , For the weighting coefficients, satisfying It can be adjusted according to actual needs (such as the default). , ).

[0114] As an optimization of the present invention, the individualized benchmark modeling stage is entered within the first 3 minutes after the immersion is started.

[0115] During this stage, the initial heart rate, blood oxygen, and skin electrical signals of the bather at rest are automatically recorded to establish a personalized dynamic baseline.

[0116] The system takes into full account the significant differences in hydrogen sulfide tolerance among the elderly, athletes, or individuals with underlying medical conditions. Once the system detects heart rate variability... Exceeding the initial baseline by 30%, or blood oxygen saturation If an absolute drop of more than 3% occurs, even if the concentration of hydrogen sulfide in the environment is within safe standards, the logic control layer will immediately determine that the person bathing is in a state of physiological overload. At this point, the priority will be quickly switched from therapeutic effect to safety, and the corresponding high-level protection plan will be implemented.

[0117] The fourth step is to perform multivariate coupled bath parameter decision-making and dynamic compensation.

[0118] The process employs a model predictive control (MPC) algorithm to coordinate the scheduling of multiple actuators while meeting safety constraints. The first step is dynamic pH adjustment, where food-grade citric acid or alkaline buffer solution is precisely added to the circulation pipeline via the dosing actuator. Since the effect of pH on the forms of hydrogen sulfide is exponential, a hierarchical PID control strategy is used.

[0119] The first stage uses feedforward prediction based on the water replenishment flow rate and preset concentration to calculate the basic dosage.

[0120] The second stage performs closed-loop correction based on real-time pH sensor feedback.

[0121] To ensure the chemicals achieve molecular-level homogeneity before entering the bath, the dosing point is strategically located at the Venturi jet mixer after the circulation pump. The Venturi jet mixer has unique spiral guide vanes that generate high-intensity turbulent shear, allowing the chemicals to mix instantaneously with the hot spring water.

[0122] When supplementing the components, according to Calculated values ​​and The real-time decrease in concentration drives a precision proportional pump to dynamically replenish the hydrogen sulfide concentrate.

[0123] For water temperature control, the amount of hot and cold water on the secondary side is adjusted by a plate heat exchanger to lock the water temperature within the ideal therapeutic window of 38℃ to 42℃.

[0124] In terms of environmental control, variable frequency fresh air systems are based on... The growth slope is dynamically adjusted to regulate the exhaust fan frequency. A gradient control algorithm based on spatial concentration is used to identify the centroid location with the highest hydrogen sulfide concentration and guide the airflow in a directional manner, ensuring that the hydrogen sulfide concentration in the breathing zone remains below the legally mandated safety threshold of 10 mg / m³.

[0125] In addition, the present invention also provides a system for implementing the above method. The system consists of a perception layer, a logic control layer, and an execution layer.

[0126] In addition to the aforementioned sensor array, the perception layer places particular emphasis on the engineering rationality of the sensor layout. For example, the air quality sensor array adopts a cross-coverage layout, effectively eliminating monitoring blind spots. The logic control layer is carried by an edge computing gateway, which integrates a high-performance processing chip and runs a concentration prediction algorithm based on Long Short-Term Memory (LSTM) networks. This algorithm can analyze the temporal characteristics of historical monitoring data and predict the concentration trend within the next 5 minutes, thus providing advance command output to the execution layer. The execution layer integrates a liquid replenishment unit, a pH adjustment unit, a temperature control unit, and an environmental control unit. Each unit has an independent PLC control module and is subject to unified coordination by the edge gateway.

[0127] Furthermore, in practical applications, a safety redundancy module is nested within the logic control layer. This module employs hardwired logic independent of the algorithm controller. When the ambient hydrogen sulfide concentration... If the concentration of hot spring water suddenly reaches 20 mg / m³, or if a bather triggers the emergency stop switch on the edge of the bathtub, the safety redundancy module will bypass all algorithm judgments, directly force the liquid replenishment pump to shut down and cut off the relevant power supply, push the variable frequency exhaust fan to run at its rated power, and open the electric large-diameter drain valve at the bottom to remove the hot spring water in the pool in the shortest possible time, ensuring the personal safety of the bather.

[0128] Furthermore, the system possesses comprehensive data backtracking and remote management capabilities. The parameters and physiological response curves for each bathing session are uploaded to a cloud database via an encrypted protocol. Through deep learning of massive amounts of clinical data, the system can continuously optimize the efficacy evaluation model in step three, achieving self-evolution of the algorithm. For distributed hot spring baths, maintenance personnel can remotely monitor the operational status of each bathing unit in real time, achieving a leap from single-machine intelligence to clustered management.

[0129] To further demonstrate the superiority and reliability of the technical solution of this invention, specific engineering embodiments and comparative experimental data are provided below.

[0130] Example 1: See Figure 1 The parameter optimization system described in this invention was deployed in the hydrogen sulfide hot spring treatment room of a rehabilitation medical center. The effective volume of the bathing pool is 2.5 cubic meters, and the design objective is to maintain a constant high level of molecular hydrogen sulfide concentration in the water at 50 mg / L.

[0131] In the initial stage, the system automatically calibrates the initial parameters:

[0132] The makeup water has a pH of 7.6, a temperature of 39.5°C, and a dissolved hydrogen sulfide concentration of 150 mg / L. Based on the gas-liquid equilibrium model of this invention, the following calculations are first performed at the current water temperature. :

[0133] ;

[0134] Pick (25℃), temperature effect is negligible.

[0135] Calculate the proportion of molecular hydrogen sulfide :

[0136] ;

[0137] because Since it is much smaller than the first two terms, it can be ignored. Therefore:

[0138] ;

[0139] Therefore, the actual concentration of reactive molecular hydrogen sulfide in water is... The therapeutic threshold of 50 mg / L was not reached. To achieve the target molecular concentration, the required total dissolved hydrogen sulfide concentration should be:

[0140] ;

[0141] The logic control layer immediately issues a compound instruction:

[0142] The metering pump of the pH adjustment unit starts, injecting 10% concentration of food-grade organic acid at an appropriate rate to lower the pH from 7.6 to the target range.

[0143] Simultaneously, the replenishment unit activates, replenishing the hydrogen sulfide concentrate at a pulsed frequency to gradually increase the total dissolved hydrogen sulfide to approximately 305 mg / L. During the adjustment process, the system monitors the pH in real time and fine-tunes the amount of acid added to ensure the pH remains stable between 6.5 and 7.2, maintaining a high pH level. value.

[0144] After 15 minutes of immersion, the bather's increased core body temperature led to enhanced metabolism, resulting in increased sweating and a rising pH in the water (detected to reach 7.15). Furthermore, the bather's movements caused increased surface undulation. The environmental monitoring unit detected the concentration of hydrogen sulfide in the breathing zone. The concentration rapidly increased from 2.1 mg / m³ to 6.5 mg / m³, with a growth rate of 0.8 mg / m³ / min. At this point, the logic control layer, based on model predictions, determined that the air concentration would exceed the limit within 2 minutes without intervention. It immediately increased the frequency of the variable frequency exhaust fan from 25 Hz to 48 Hz and activated the fresh air intake fan. Simultaneously, the system fine-tuned the acid dosage based on real-time pH fluctuations, bringing the pH back down to approximately 6.9, thereby suppressing excessive hydrogen sulfide emission.

[0145] The entire immersion process lasted 25 minutes. Despite the presence of complex random variables such as the bather's movement and the interference of metabolic products, the concentration of molecular hydrogen sulfide in the water remained within a narrow range of 48.5 mg / L to 51.2 mg / L, the peak concentration of hydrogen sulfide in the air did not exceed 7.2 mg / m³, and the bather's heart rate and blood oxygen remained within their individual baseline healthy range.

[0146] Comparative Example 1: Under the same physical environment, a traditional static control method was used. That is, the water quality was adjusted to the target parameters once before the bathing started, and hydrogen sulfide was replenished only at a preset fixed frequency during the bathing process (the replenishment amount was based on the average value of Example 1). It did not have the function of online closed-loop pH regulation and physiological feedback linkage.

[0147] At the beginning of the experiment, the initial parameters were set to the same level (pH=7.6, water temperature 39.5℃, total dissolved H2S=150 mg / L). However, after 12 minutes of immersion, due to the lack of real-time intervention for pH fluctuations, the pH value of the water gradually rose to 8.1 as metabolites accumulated. At this point, the molecular percentage was calculated. :

[0148] ;

[0149] The concentration of active ingredients in water dropped sharply. The dosage was far below the required medical dose, resulting in a significant impairment of therapeutic efficacy.

[0150] More seriously, after about 18 minutes of immersion, due to increased water surface evaporation and the ventilation system operating at a consistently low power, the hydrogen sulfide concentration in the breathing zone accumulated to 16.5 mg / m³. Because the system could not monitor the bather's physiological state, it failed to take any emergency measures when the bather experienced mild dizziness (heart rate increased to 125 bpm, blood oxygen level dropped to 92%). The system ultimately required manual intervention for emergency shutdown, demonstrating extremely poor safety.

[0151] Table 1 records the comparison data of several key technical indicators between Example 1 and Comparative Example 1 during the 25-minute immersion cycle:

[0152] Table 1: Comparison of operational data between embodiments of the present invention and comparative examples;

[0153]

[0154] Note: The target concentration achievement rate is defined as the average ratio of the measured molecular concentration to the target value of 50 mg / L. In Comparative Example 1, the molecular concentration was much lower than the target due to the increased pH, resulting in a lower achievement rate.

[0155] The quantitative data above clearly demonstrates that the optimization method and system described in this invention have achieved a qualitative leap in the stability control of the core active ingredients. The precipitous drop in active ingredients caused by pH loss of control in Comparative Example 1 is perfectly avoided in this embodiment by multivariate closed-loop control. Furthermore, in terms of safety, this invention completely eliminates the risk of poisoning from hydrogen sulfide hot springs through a dual physiological-environmental threshold locking strategy.

[0156] In the replenishment logic of the execution layer, the system not only considers the current concentration deviation, but also pre-calculates the water disturbance and thermal balance changes caused by the replenishment action itself through algorithms. The precision proportional pump of the replenishment unit is driven by high-frequency pulses and can perform multiple micro-jet injections per second. Combined with the Venturi jet, the high concentration of hydrogen sulfide replenishment solution is diluted thousands of times before entering the pool, eliminating the risk of chemical burns to the skin of bathers from the physical level due to local high-concentration clusters.

[0157] The fresh air strategy of this invention is not a simple exhaust system, but rather a directional flow field organization calculated through fluid dynamics simulation. Based on data transmitted from an air quality sensor array, the system calculates the diffusion flux vector field of hydrogen sulfide molecules. A slight negative pressure gradient (approximately 5-10 Pa) is maintained between the variable frequency exhaust fan and the make-up air fan, ensuring that hydrogen sulfide gas does not diffuse into the public area outside the bathroom, while also ensuring a constant, slow, directional flow of fresh air around the bather's face, greatly improving the comfort and safety of the bathing experience.

[0158] In the system's hardware and software co-design, the parameter analysis module inside the edge computing gateway uses a Kalman filter algorithm to denoise the raw sensor data. Due to strong electromagnetic interference and water flow noise in the hot spring environment, the raw signal often contains high-frequency jitter. The Kalman filter, through a state-space model and combined with physical laws (such as pH changes not occurring in a step within 0.1 seconds), performs real-time optimal estimation of the measured values, thereby avoiding frequent controller malfunctions and system oscillations.

[0159] In practical use, the logic control layer can adjust and optimize the target online, appropriately increase the upper limit of water temperature, and simultaneously strengthen the monitoring weight of physiological feedback.

[0160] The jet mixer in the replenishment unit employs a double-helix structure for its internal spiral guide vanes, made of Hastelloy alloy or special ceramics resistant to strong acids and alkalis. When the water flow in the main circulation pipeline passes through the narrowing section of the jet mixer, a negative pressure is generated due to the Bernoulli effect, drawing in hydrogen sulfide gas or concentrated liquid. The double-helix structure creates a strong swirling flow, significantly increasing the renewal rate of the gas-liquid contact surface.

[0161] Example 2: Based on Example 1, this example further describes in detail how the control decision module in the edge computing gateway uses a Long Short-Term Memory (LSTM) network to predict the hydrogen sulfide concentration for the next 5 minutes, and solves for the optimal control command based on the Non-Dominated Sorting Genetic Algorithm (NSGA-II) to achieve rolling optimization control.

[0162] The specific process is as follows:

[0163] Data Acquisition and Preprocessing: The sensing layer continuously acquires water quality parameters (dissolved hydrogen sulfide concentration) at a frequency of 1 Hz. pH value, water temperature Oxidation-reduction potential Electrical conductivity ), environmental parameters (air hydrogen sulfide concentration) Wind speed Ambient temperature relative humidity ) and physiological parameters (heart rate) Blood oxygen saturation ).

[0164] The edge computing gateway maintains a sliding time window of 900 seconds (15 minutes), and all historical data within the window constitutes the input feature matrix. Its dimensions are ,in In this embodiment, the feature dimension is... Take 12 (including all 12 parameters mentioned above). All data is normalized before being input into the LSTM network.

[0165] LSTM Network Structure and Prediction: The LSTM network employs a three-layer stacked structure, with each layer containing 128 hidden units. The input layer receives multidimensional features from the past 900 time steps, and the output layer is a fully connected layer that outputs the predicted sequence for the next 300 time steps (5 minutes), including the predicted value of dissolved hydrogen sulfide concentration. Predicted values ​​of hydrogen sulfide concentration in air The activation function uses The loss function is mean squared error (MSE). The network was trained offline, and the training dataset was derived from historical bathing records, covering operational data under different seasons, different bathers, and different initial water qualities, totaling more than 100,000 samples. The Adam optimizer was used during training, with a learning rate of 0.001, a batch size of 64, and 100 training epochs.

[0166] During online operation, every minute, the edge computing gateway updates the input matrix using the latest 900 seconds of data, and predicts the next 5 minutes' worth of data using an LSTM network. and Trajectory. To adapt to environmental changes, the system supports incremental learning once a week, using newly collected data to fine-tune the network weights.

[0167] The NSGA-II multi-objective optimization is as follows: In each control cycle (1 minute), based on the concentration trajectory predicted by LSTM for the next 5 minutes, and combined with the current state, a set of optimal control command sequences is solved. ,in Representing the The minute-by-minute control command vector includes:

[0168] replenishment pump frequency (0-50 Hz);

[0169] Acid pump frequency (0-30 Hz);

[0170] Alkali pump frequency (0-30 Hz);

[0171] Fresh air exhaust fan frequency (0-60 Hz);

[0172] Temperature control valve opening (0-100%).

[0173] The objective function is defined as follows:

[0174] Minimum concentration deviation: ;

[0175] in, This is the integral of the concentration deviation, in mg·s / L; Let be the predicted concentration of molecular hydrogen sulfide at time t (mg / L), derived from the predicted... The real-time pH and water temperature are calculated using a formula. The target molecular state concentration is 50 mg / L in this embodiment; the integration interval of 0~300 seconds corresponds to the next 5 minutes.

[0176] The risk of exceeding air concentration limits is minimal. ;

[0177] in, This represents the risk score for exceeding air concentration limits, expressed in mg·s / m³. 10 represents the predicted concentration of hydrogen sulfide in the air at time t (mg / m³); 10 represents the safety threshold (mg / m³).

[0178] Minimal energy consumption: ;

[0179] in, The energy consumption integral is dimensionless (or the unit is Hz²·min). , , The energy consumption coefficients are 0.1, 0.05, and 0.02 in this embodiment, with units of Hz⁻²·min⁻¹, Hz⁻²·min⁻¹, and Hz⁻²·min⁻¹, respectively. , , The frequencies (in Hz) of the replenishment pump, acid pump, and exhaust fan are respectively assumed to be piecewise constants within the optimization time interval.

[0180] The constraints include the following:

[0181] Actuator range constraints: Hz, Hz, Hz, Hz, ;

[0182] Actuator rate of change constraint: Hz / min, Hz / min, Hz / min, Hz / min, / min;

[0183] Safety constraints: mg / m³, and the calculated physiological risk index .

[0184] The NSGA-II algorithm parameters are set as follows:

[0185] The population size is 100, the number of iterations is 200, the crossover probability is 0.9, and the mutation probability is 0.1. Simulated binary crossover (SBX) and polynomial mutation are used. The Pareto front solution set is obtained after optimization, and the system calculates the solution based on preset preference weights (e.g., ...). A compromise solution is selected from the Pareto front, and only the instructions for the first control step (minute 1) are executed. The prediction optimization is re-executed in the next minute to achieve rolling time-domain control.

[0186] Under the same physical environment, the operating effects of Example 1 and this example (using LSTM+NSGA-II) were compared. In this example, the standard deviation of molecular hydrogen sulfide concentration was further reduced to 0.8 mg / L (1.2 mg / L in Example 1), the time for exceeding the standard for air hydrogen sulfide concentration remained 0, and energy consumption was reduced by 12%. This demonstrates that prediction-based multi-objective optimization can more accurately respond to concentration changes in advance, reduce overshoot, and improve system stability and economy.

[0187] Example 3: This example addresses the interference of human sweat, sebum, and other metabolic products on the chemical balance of water during bathing, and describes in detail how to utilize conductivity... and redox potential The rate of change of the emission rate is dynamically corrected to improve the feeding accuracy.

[0188] When bathers enter a hot spring, electrolytes such as NaCl and urea in their sweat instantly increase the water's conductivity, leading to changes in ionic strength and affecting the activity coefficient of hydrogen sulfide and the Henry's constant. Simultaneously, reducing substances in sebum (such as fatty acids) consume dissolved oxygen in the water, causing... This decrease accelerates the oxidation of sulfide ions. Without compensation, traditional models will underestimate the actual escape rate, resulting in a decrease in the concentration of active ingredients.

[0189] Under laboratory conditions, simulating the composition of human sweat (referencing ISO 10555 standard), a sweat-simulating solution was gradually added to a hydrogen sulfide solution at a constant temperature (40°C), while simultaneously measuring changes in conductivity. And the decay rate of hydrogen sulfide concentration. An empirical relationship between the rate of change of conductivity and the increment of the emission rate was established through regression analysis:

[0190] ;

[0191] in, This is a conductivity correction factor, dimensionless. The value is the sweat dilution calibration factor, with units of s·cm / mS. In this embodiment, it is calibrated to 0.03 s·cm / mS through experiments. This is the rate of change of electrical conductivity, expressed in mS·cm⁻¹·s⁻¹. The value represents electrical conductivity, expressed in mS / cm.

[0192] Similarly, add sebum extract to the solution and measure... The relationship between the rate of decrease and the rate of sulfur ion oxidation is obtained as follows:

[0193] ;

[0194] in, This is a redox potential correction factor, dimensionless; This is the oxidation compensation calibration coefficient, in units of s / mV. In this embodiment, it is taken as 0.2 s / mV. This represents the rate of change of redox potential, expressed in mV / s. This represents the redox potential, expressed in mV.

[0195] The comprehensive correction model is as follows:

[0196] During the actual immersion process, the system performs real-time calculations. and (Noise is removed using a moving average filter with a window length of 10 seconds), and the overall correction factor is dynamically calculated:

[0197] ;

[0198] in, This is a dimensionless correction factor. It is applied when conductivity or... When significant changes occur (e.g.) mS·cm⁻¹·s⁻¹), the corrected dissipation amount Used for replenishment calculation:

[0199] ;

[0200] in, The uncorrected hydrogen sulfide mass flow rate is calculated according to the formula, in mg / s. The corrected mass flow rate is expressed in mg / s. Additionally, to eliminate sensor drift interference, the system automatically performs zero-point calibration every 24 hours.

[0201] Based on Example 1, the metabolic compensation function of this example was enabled, and compared with the control group without compensation. After bathing for 15 minutes, the concentration of molecular hydrogen sulfide in the uncompensated group decreased from 50 mg / L to 42 mg / L due to sweat accumulation, while the concentration in the compensated group remained at around 49 mg / L through real-time supplementation, with the fluctuation range reduced by 80%. This demonstrates that this example effectively counteracts the interference of human metabolism on water quality.

[0202] Example 4: This example addresses the problem of uneven diffusion of hydrogen sulfide gas in the bathing space. It describes in detail how to use a multi-point sensor array to identify the centroid of pollution and link it with a variable frequency fan to form a directional airflow, thereby ensuring the air quality in the breathing zone of the bather.

[0203] The sensor array layout is as follows:

[0204] Electrochemical hydrogen sulfide sensors were installed at the four corners of the ceiling in the bathing room, and their coordinates were set as follows: , , , ,in The room length is in meters. The room width is (m); a sensor is installed 30 cm directly above the bather's head, with coordinates as follows: All sensors synchronously acquired concentration data at a frequency of 5 Hz, and the concentration values ​​were recorded as follows: , , , and (Unit: mg / m³), and transmitted to the edge computing gateway via CAN bus.

[0205] The concentration gradient and centroid are calculated as follows:

[0206] Using the finite difference method, the horizontal concentration gradient is calculated based on the concentration values ​​at the four corners:

[0207] ;

[0208] in, This is a concentration gradient vector, with units of mg / m³. 4 ; and These are the partial derivatives in the x and y directions, respectively. and These represent the room length and width (m), respectively. The gradient direction indicates the main diffusion direction of pollutants. Simultaneously, the concentration-weighted centroid location is calculated:

[0209] ;

[0210] in, The coordinates of the centroid are (m); For the first Coordinates of each sensor (m); For the first The concentration values ​​(mg / m³) of each sensor are measured. When the concentration at a certain point is significantly higher than that at other points, the centroid will move closer to that point, indicating the location of the pollution source.

[0211] The directional airflow control algorithm is as follows:

[0212] Four variable frequency exhaust fans are installed around the room (corresponding to the four corners), and a fresh air supply fan is installed in the center of the ceiling. (Based on centroid coordinates) Calculate the target frequency for each exhaust fan:

[0213] ;

[0214] in, For the first The target frequency (Hz) of each fan; The minimum operating frequency for the fan is 10 Hz in this embodiment; The maximum operating frequency of the fan is 60 Hz in this embodiment; For the first From the fan to the core Euclidean distance (m); For all The maximum value in, The minimum value is set. Simultaneously, the frequency of the make-up air fan is set to 80% of the sum of the frequencies of all exhaust fans to maintain a slight negative pressure (5-10 Pa). To prevent airflow short-circuiting, the louvers at each exhaust vent can automatically adjust the blade angle according to the gradient direction, causing the airflow to flow in the opposite direction of the gradient, directly guiding the polluted gas to the exhaust vent.

[0215] Based on Example 1, the effects of directional airflow organization with and without activation were compared. Under the same dissipation conditions, when not activated, the hydrogen sulfide concentration in the breathing zone reached a maximum of 7.2 mg / m³, and fluctuated significantly; after activation, due to precise airflow guidance, the peak concentration in the breathing zone decreased to 4.5 mg / m³, and the concentration distribution was uniform, significantly improving the comfort of the bather.

[0216] Comparative Example 2: In practical use, to verify the key role of physiological sign monitoring and feedback control in this invention, Comparative Example 2 was set up. The system structure is basically the same as that of Example 1, but the physiological sign monitoring unit is removed, and control is based solely on environmental and water quality parameters.

[0217] The control logic has been modified to maintain the concentration of molecular hydrogen sulfide at around 50 mg / L. When the concentration of hydrogen sulfide in the air exceeds 8 mg / m³, the exhaust fan is activated, and when it is below 5 mg / m³, the exhaust fan is reduced.

[0218] The subjects in the experiment were the same bath recipients (resting heart rate 75 bpm, blood oxygen 98%).

[0219] After the bath began, the system automatically adjusted the pH and feed according to the water quality, operating smoothly for the first 10 minutes. At the 12-minute mark, the bather's slight movement caused their heart rate to rise to 100 bpm, but the system did not detect this physiological change and continued operating according to its original strategy. At the 15-minute mark, due to the persistently high heart rate, the bather experienced mild dizziness, while the air hydrogen sulfide concentration was only 6.2 mg / m³ (without triggering accelerated ventilation), yet the bather was already on the verge of hypoxia. It wasn't until the 18-minute mark that the bather felt unwell and stopped the system; subsequent records showed that blood oxygen levels had dropped to 91%. This comparative study demonstrates that a system without physiological feedback cannot respond promptly to individual physiological overload, posing a serious safety hazard.

[0220] Comparative Example 3: The system structure of this comparative example is the same as that of Example 1, but the step two is closed. / Conductivity correction term (i.e. (Constantly 1). The immersion process is the same as in Example 1.

[0221] When the immersion bath reached 10 minutes, the conductivity increased due to sweating by the bather. However, the system did not compensate for the dissipation rate, leading to an underestimation of the actual dissipation and insufficient feed replenishment. The concentration of molecular hydrogen sulfide gradually decreased to 42 mg / L (at 15 minutes). Although the system increased feed replenishment later based on the concentration deviation, the lag was significant, with concentration fluctuations reaching ±5 mg / L, far exceeding the ±1.2 mg / L in Example 1. This indicates that without metabolic compensation, the model accuracy decreases, and the stability of the components is compromised.

[0222] In actual system cabling and installation, all signal lines use corrosion-resistant shielded twisted-pair cables and are protected by acid- and alkali-resistant PVC flexible conduits. The sensor mounting base adopts a modular design, supporting press-fit insertion and removal and automatic cleaning functions, further reducing the difficulty of later system maintenance. For large-scale hot spring centers, the system supports cascading of edge computing gateways to achieve parallel management of hundreds of bathing positions. Each position has an independent closed-loop control algorithm instance, ensuring system robustness during large-scale applications.

[0223] Example 5: In the above examples, due to the failure to consider the significant differences in individual skin permeability, the actual absorbed dose of different bathers fluctuates greatly, resulting in inconsistent therapeutic effects. Furthermore, some sensitive individuals face the risk of poisoning due to excessively rapid absorption. How to upgrade the control target from environmental concentration to human absorption dose, achieving precise individualized dose delivery, is the technical problem this example aims to solve.

[0224] This embodiment, based on Embodiment 1, adds a transdermal absorption kinetics modeling and real-time feedback module. It uses the absorption rate and cumulative absorbed dose as the core constraints of the control system to achieve precise individualized dose delivery. The overall system architecture follows the sensing layer, logic control layer, and execution layer of Embodiment 1, with the addition of a transdermal absorption model calculation unit in the logic control layer. This unit is deeply integrated with the existing gas-liquid balance model, safety risk index, and MPC controller.

[0225] Specifically as follows:

[0226] skin permeability With activation energy The in vitro calibration was conducted as follows: Before system deployment, in vitro skin permeability experiments were performed on different populations (age, gender, skin type). A Franz diffusion cell was used to measure the steady-state flux of hydrogen sulfide through the in vitro skin sample at a constant temperature of 37°C, and the baseline permeability coefficient was calculated. .

[0227] Experimental data show that differences in stratum corneum thickness among individuals lead to exist to Between m / s.

[0228] The system has a built-in lookup table that initializes based on the basic information entered by the bather (age, gender, skin dryness). .

[0229] The osmotic flux was further determined through temperature-varying experiments (30℃, 37℃, 40℃), and the activation energy was obtained by fitting the Arrhenius equation. kJ / mol (average value).

[0230] Blood perfusion index The real-time extraction is as follows:

[0231] The wearable physiological monitoring module (flexible fabric electrodes) acquires green light (525 nm) and infrared light (940 nm) signals via photoplethysmography (PPG). An adaptive filtering algorithm is used to extract the pulse wave amplitude and calculate the blood perfusion index. : ;

[0232] in, The value of the infrared AC component at time t is dimensionless. Let be the amplitude of the DC component of the infrared light at time t, which is dimensionless. Under resting conditions... The average value was taken 3 minutes before immersion. The blood flow enhancement coefficient was calibrated through a preliminary experiment. That is, a 10% increase in the blood perfusion index can increase the permeability coefficient by 3%.

[0233] Skin temperature The temperature is obtained as follows: using an infrared temperature sensor installed on the bathtub wall (aimed at the bather's back) or a contact temperature sensor integrated into a wearable module to collect skin temperature in real time. The unit is K. When direct measurement is not possible, the predicted core body temperature is used. (Estimated by the physiological monitoring unit based on heart rate, skin conductance signals, etc.) and ambient temperature Based on calculations using a human body thermal balance model:

[0234] ;

[0235] in, This is an empirical coefficient, taken as 0.3; The ambient temperature is measured in Kelvin (K) and is collected in real time by the environmental monitoring unit.

[0236] Effective skin contact area The estimation steps are as follows:

[0237] According to the height of the bather (m), weight (kg) Estimate body surface area using the Du Bois formula (m²):

[0238] ;

[0239] Effective skin contact area during bathing Take the body surface area multiplied by the immersion coverage ratio. (Usually taken as 0.7):

[0240] ;

[0241] in, It is a dimensionless constant and can be adjusted between 0.6 and 0.8 depending on the bathing posture (sitting / lying down).

[0242] In practical applications, to further improve model accuracy, a first-order compartment model is introduced to describe the dynamic changes in hydrogen sulfide concentration in capillaries. It is assumed that the capillaries are ideal mixing chambers with an effective volume of... (L), the rate at which hydrogen sulfide enters the capillaries is the absorption rate. (mg / s), the rate of clearance from capillaries (entering systemic circulation or being metabolized) follows first-order kinetics, and the clearance rate constant is... (s⁻¹), then Satisfies the differential equation: ;

[0243] Initial conditions .

[0244] The equation is solved online using numerical integration (such as the Euler method), with a step size of 1 second. Parameters and This can be determined through literature values ​​or individualized experiments. Based on physiological data of human skin capillaries, [the following values ​​can be obtained]. L, s⁻¹ (corresponding to a half-life of approximately 69 seconds).

[0245] In practical engineering applications, if Much lower than the concentration in water It can be approximated as To simplify calculations, this embodiment uses a complete first-order room model for real-time updates, balancing accuracy and computational overhead.

[0246] The steps for online calculation of transdermal absorption rate and cumulative dose are as follows:

[0247] Every second, the edge computing gateway adjusts its settings based on the current... (Calculated in real time by water quality sensors and pH) , Update skin permeability :

[0248] ;

[0249] in, K (37℃) J / (mol·K).

[0250] Then, in combination with the current situation (Obtained by integrating from the previous moment), calculate the absorption rate. :

[0251] ;

[0252] Next, the first-order room model is used to update the next time step. : ;

[0253] in s.

[0254] Finally, the cumulative absorbed dose Obtained by summing the absorption rates: ;

[0255] In the model predictive control in step four, the original objective function is... (Concentration deviation integral) is replaced with absorbed dose deviation integral:

[0256] ;

[0257] in, This is the integral of the absorbed dose deviation, in mg·s;

[0258] The concentration trajectory is predicted based on LSTM and the future absorbed dose trajectory is predicted based on the current skin condition, in mg.

[0259] The desired absorption dose curve is expressed in mg and is set as a linear or step function according to the treatment requirements (e.g., rapidly loading to 3 mg in the first 5 minutes, and then maintaining stable absorption to a total of 10 mg in the next 20 minutes).

[0260] The new absorption rate safety constraints are as follows:

[0261] ;

[0262] in, The safe absorption rate threshold is set at 0.5 mg / min (for a 70 kg adult) based on toxicological data. If the absorption rate is predicted to exceed the limit in the future, the controller will prioritize reducing the feed rate or increasing the pH to reduce the molecular concentration, and lower the water temperature if necessary.

[0263] Cumulative absorbed dose Incorporate safety risk index and set toxicity threshold dose mg (referencing OSHA short-term exposure limits), weighted by the following factor: , , Revised security risk index for:

[0264] ;

[0265] in, The safe threshold dose of hydrogen sulfide in air is expressed in mg·min / m³. and These are the baseline values ​​for heart rate (bpm) and blood oxygen saturation (%), respectively. , .when When the safety priority mode is triggered, the fresh air is forced to be fully turned on and the material replenishment is stopped.

[0266] Twenty volunteers (aged 30-65, half male and half female) were selected from a rehabilitation center and randomly divided into two groups. Group A followed the protocol of Example 1 (non-absorption model), and Group B followed the protocol of this example. Each volunteer underwent a 25-minute immersion bath, with a target molecular concentration of 50 mg / L in the water. The concentration of hydrogen sulfide in subcutaneous tissue fluid was collected using microdialysis technology to indirectly assess the absorbed dose.

[0267] Table 2: A comparison of key indicators between Example 5 and Example 1 is as follows;

[0268]

[0269] This embodiment introduces a transdermal absorption kinetic model, extending the control loop from water quality-environment to a three-loop coupling of human body-water quality-environment, achieving a qualitative leap from concentration maintenance to precise dose delivery. The temperature and blood flow correction terms in the model are deeply nested with the original gas-liquid balance and dissipation models (for example, skin temperature is affected by both water and air temperature, while water temperature is controlled by a temperature control unit), forming a multi-physics synergistic optimization. Regardless of individual skin differences, the system automatically adjusts bathing parameters to ensure each bather receives a consistent and safe hydrogen sulfide absorption dose, truly realizing personalized precision medicine in hot spring therapy.

[0270] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the invention.

[0271] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. It should be noted that any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for optimizing parameters of hydrogen sulfide hot spring bathing, characterized in that, Includes the following steps: Step 1: Construct a real-time data acquisition field based on a multi-source sensing array; deploy a sensor network consisting of a water quality monitoring unit, an environmental monitoring unit, and a physiological characteristic monitoring unit within the immersion space; the water quality monitoring unit collects in real-time data on dissolved hydrogen sulfide concentration, hydrogen ion concentration index, water temperature, redox potential, and conductivity in the immersion water; the environmental monitoring unit collects in real-time data on air hydrogen sulfide concentration, ambient temperature, relative humidity, and airflow velocity at the breathing zone height within the immersion space; the physiological characteristic monitoring unit acquires the bather's real-time heart rate, blood oxygen saturation, predicted core body temperature, and skin surface electrical signals through wearable biosensors; All collected data is transmitted via fieldbus to the edge computing gateway for synchronization and preprocessing; Step 2: Establish a nonlinear dynamic model of hydrogen sulfide gas-liquid equilibrium; use the water quality parameters obtained in Step 1 to calculate the real-time proportion of molecular hydrogen sulfide in the water; based on the second-order dissociation constant of hydrogen sulfide in aqueous solution, combine the Henry's law correction formula to calculate the Henry coefficient at the current water temperature, and derive the theoretical equilibrium partial pressure of hydrogen sulfide on the water surface. By introducing the wind speed in the spatial flow field as a disturbance factor, a dissipation rate model is constructed to calculate the mass flow rate of hydrogen sulfide dissipating from the liquid phase to the gas phase per unit time. Step 3: Construct a safety and efficacy evaluation system for immersion baths based on physiological feedback; A therapeutic efficacy weighting factor is defined, which is positively correlated with the concentration of molecular hydrogen sulfide and water temperature; a safety risk index is defined, which is a function of the cumulative exposure dose of airborne hydrogen sulfide and the deviation of the bather's physiological parameters from the baseline value. When the safety risk index exceeds a preset first safety threshold, the safety priority mode is activated; when the safety risk index is lower than the first safety threshold and the efficacy weighting factor is lower than the expected efficacy threshold, the efficacy optimization mode is activated. Step four: Perform multivariate coupled bath parameter decision-making and dynamic compensation; based on the model predictive control algorithm, with the constraints of maintaining a constant concentration of molecular hydrogen sulfide in the water and ensuring that the concentration of hydrogen sulfide in the air does not exceed the standard, calculate the required dynamic compensation amount; the compensation methods include at least one or a combination of dynamic pH adjustment, precise solubility control, spatial concentration control and feeding logic.

2. The method for optimizing hydrogen sulfide hot spring bathing parameters according to claim 1, characterized in that, In step two, the molar fraction of molecular hydrogen sulfide among all dissolved hydrogen sulfide is determined as follows: Based on the real-time collected hydrogen ion concentration index, the first-order dissociation constant and the second-order dissociation constant of hydrogen sulfide, the results are calculated according to the second-order dissociation equilibrium of hydrogen sulfide; wherein, the first-order dissociation constant is linearly related to water temperature and decreases as water temperature increases; the second-order dissociation constant is linearly related to water temperature.

3. The method for optimizing hydrogen sulfide hot spring bathing parameters according to claim 1, characterized in that, In step two, the Henry coefficient at the current water temperature is determined by an exponential function relationship based on the Henry coefficient at the reference temperature and the temperature coefficient. Based on the Henry coefficient and the molar concentration of liquid molecular hydrogen sulfide, the theoretical equilibrium partial pressure of hydrogen sulfide on the water surface is determined. The escape rate model is based on the two-film theory. The mass flow rate of hydrogen sulfide escaping from the liquid phase to the gas phase per unit time is determined by the liquid phase mass transfer coefficient, the gas-liquid contact area, and the difference between the molecular hydrogen sulfide molar concentration in the liquid phase and the interfacial equilibrium concentration. The liquid phase mass transfer coefficient is related to the wind speed in the spatial flow field and is determined by an empirical formula.

4. The method for optimizing hydrogen sulfide hot spring bathing parameters according to claim 1, characterized in that, In step two, a correction factor based on the rate of change of redox potential is introduced to correct the hydrogen sulfide mass flow rate in real time; the correction factor is linearly related to the rate of change of redox potential and is weighted by correction coefficients. The corrected hydrogen sulfide mass flow rate is the product of the correction factor and the uncorrected hydrogen sulfide mass flow rate.

5. The method for optimizing hydrogen sulfide hot spring bathing parameters according to claim 1, characterized in that, In step three, the therapeutic effect weighting factor is determined based on the ratio of molecular hydrogen sulfide concentration to target concentration and the ratio of water temperature to reference temperature. The safety risk index is determined by a weighted sum of the ratio of cumulative exposure dose to safe threshold dose of hydrogen sulfide in the air, the ratio of heart rate variability to baseline heart rate, and the ratio of blood oxygen saturation variability to baseline blood oxygen saturation. Wherein, the cumulative exposure dose is the integral of the air hydrogen sulfide concentration over time from the start of the bath to the current moment, the heart rate change rate is the absolute value of the difference between the real-time heart rate and the baseline heart rate at rest before the bath, the blood oxygen saturation change rate is the absolute value of the difference between the baseline blood oxygen saturation at rest before the bath and the real-time blood oxygen saturation; and the sum of the weighting coefficients of the weighted sum is 1.

6. The method for optimizing hydrogen sulfide hot spring bathing parameters according to claim 1, characterized in that, In step four, the dynamic adjustment of pH value adopts a graded PID control strategy: The first level is predictive control, which estimates the acid and alkali consumption based on the water replenishment flow rate and the preset hydrogen sulfide concentration. The second stage is feedback control, which performs closed-loop correction based on the real-time collected hydrogen ion concentration index; the dosing point is set at the Venturi jet mixer after the circulating pump.

7. The method for optimizing hydrogen sulfide hot spring bathing parameters according to claim 1, characterized in that, In step four, spatial concentration control is achieved through linkage with the variable frequency fresh air system: The exhaust volume is dynamically adjusted according to the slope of the increase in air hydrogen sulfide concentration to ensure that the hydrogen sulfide concentration in the breathing zone is always below 10 mg / m³. The variable frequency fresh air system adopts a gradient control algorithm based on spatial concentration. According to the concentration difference at different points provided by the sensor array, the edge computing gateway calculates the centroid of pollutant diffusion in the immersion space. By adjusting the speed of the variable frequency fan in different directions, a directional airflow organization is formed.

8. The method for optimizing hydrogen sulfide hot spring bathing parameters according to claim 1, characterized in that, In step one, the water quality monitoring unit uses a pollution-resistant gold electrode hydrogen sulfide sensor with a response time T90 of less than 30 seconds, a measurement range of 0-100 mg / L, and a resolution of not less than 0.1 mg / L; the physiological signs monitoring unit uses a flexible fabric electrode and collects pulse rate data using photoplethysmography through sensing contacts integrated into the inner wall of the bathtub or a wearable waterproof module.

9. The method for optimizing hydrogen sulfide hot spring bathing parameters according to claim 1, characterized in that, In step three, when the heart rate change rate exceeds 30% of the initial baseline or the blood oxygen saturation drops by more than 3%, it is determined to be physiological overload, and the highest level of fresh air exchange is forcibly activated and an audible and visual warning is issued.

10. A system for optimizing hydrogen sulfide hot spring bathing parameters using the method described in any one of claims 1 to 9, characterized in that, The system consists of a perception layer, a logic control layer, and an execution layer. The sensing layer includes: The integrated water quality sensor group installed on the circulating return water pipeline of the bathing pool is used to detect dissolved hydrogen sulfide concentration, hydrogen ion concentration index, water temperature and redox potential. An array of air quality sensors, distributed on the walls of the bathing pool and at a height of 30 cm above the head of the bather, is used to detect the concentration of hydrogen sulfide in the air, wind speed, and relative humidity. A waterproof biosensor module is placed on the surface of the bather's skin to monitor physiological signs; The logical control layer includes an edge computing gateway, which integrates a data acquisition module, a parameter analysis module, a gas-liquid balance modeling module, and a control decision module; the parameter analysis module is responsible for denoising and feature extraction of the perception layer data; the control decision module generates control instructions for the execution layer based on a preset multi-objective optimization algorithm. The execution layer includes: The replenishment unit includes a hydrogen sulfide concentrate storage tank, a precision proportioning pump, and an electromagnetic flow meter; pH adjustment unit, including acid / alkali reagent tank, metering pump and jet mixer; Temperature control unit, including electric proportional regulating valve and plate heat exchanger; The environmental control unit includes a variable frequency exhaust fan, a fresh air supply fan, and automatic louvers.

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