Ship tail shaft sealing self-balancing air control device

Abstract

The invention relates to the technical field of ship sealing systems, in particular to a ship tail shaft sealing self-balancing air control device which comprises a double-channel redundancy integrated control valve set and a special intelligent control system, and the valve set adopts an integrated main block to integrate an active control channel and a standby safety channel. The intelligent control system collects working condition data through an environment sensing module, calculates a comprehensive environment index through a data fusion module, dynamically adjusts pressure based on a fuzzy PID algorithm, and meanwhile has the functions of automatic fault switching and predictive maintenance. The problems that in the prior art, a ship tail shaft sealing device is lagged in control and insufficient in reliability are solved, the pressure control precision is high, sealing gas supply is uninterrupted, sealing ring abrasion and operation and maintenance cost can be reduced, and the device is suitable for ship tail shaft sealing scenes.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ship sealing systems. BACKGROUND

[0002] The stern shaft sealing device of a ship forms an air curtain by injecting constant pressure air into a sealing cavity, which is the key to preventing seawater intrusion and lubricating oil leakage. The existing technology has the following problems:

[0003] Control strategy lag: traditional control methods (such as classic PID) cannot effectively respond to nonlinear, strongly coupled pressure fluctuations caused by changes in ship draft and sea state disturbances (roll and pitch caused by waves), resulting in a lag in response, unstable sealing pressure, and accelerated wear of the sealing ring.

[0004] Insufficient structural reliability: existing systems are mostly connected by dispersed pipelines, which have inherent defects such as many joints, easy leakage, large volume, and inconvenient maintenance, and generally lack redundant backups that can automatically switch in the event of a fault, resulting in low overall system reliability.

[0005] Although existing technologies attempt to introduce a single sensor or a general control algorithm, they fail to systematically and integrally integrate a special intelligent control algorithm for the special dynamics of the "ship-sealing" system with a highly reliable hardware execution structure. SUMMARY

[0006] To overcome the problems of control strategy lag, insufficient structural reliability, and insufficient integration of algorithms and hardware in existing technologies, the present application provides a self-balancing air control device for a ship stern shaft sealing.

[0007] The technical solution adopted by the present application to achieve the above-mentioned purposes is as follows: a self-balancing air control device for a ship stern shaft sealing, comprising a dual-channel redundant integrated control valve group and a special intelligent control system, the special intelligent control system being electrically connected with the dual-channel redundant integrated control valve group;

[0008] The dual-channel redundant integrated control valve group comprises a main block, an electrically controlled switching valve, a common converging cavity, and a pluggable filter element module. The main block has a main control channel and a standby safety channel arranged in parallel inside. The main control channel is sequentially provided with an electrically controlled pressure reducing valve, a flow meter, and an electrically controlled flow regulating valve. The standby safety channel is provided with a mechanical pressure reducing valve and a mechanical flow regulating valve. The inlet end of the electrically controlled switching valve is connected with the outlets of the main control channel and the standby safety channel, respectively. The outlet end is in communication with the common converging cavity. The common converging cavity is provided with a pressure sensor and a temperature sensor. The pluggable filter element module is arranged in a total air inlet path. The total air inlet path is connected with an external air source. The air filtered by the pluggable filter element module from the external air source is delivered to the main control channel and the standby safety channel, respectively.

[0009] The special intelligent control system comprises an environment perception module, a data fusion module and an intelligent controller, which are connected with each other; the environment perception module comprises a draft depth sensor, a three-axis acceleration sensor and a main shaft speed sensor, the data fusion module is used for processing the data collected by the environment perception module, and the intelligent controller is electrically connected with an electric control pressure reducing valve, an electric control flow regulating valve, an electric control switching valve, a pressure sensor and a temperature sensor.

[0010] Preferably, the main block is made of metal material and is integrally casted or processed into shape, and the electric control switching valve is an electric control two-position two-way switching valve.

[0011] Preferably, the environment perception module collects the draft depth of the ship in real time through the draft depth sensor, the three-axis acceleration sensor and the main shaft speed sensor. a three-axis acceleration resultant vector a main shaft speed .

[0012] The data fusion module processes the data collected by the environment perception module as follows:

[0013] normalization processing:

[0014] .

[0015] wherein, is a draft depth normalized value, , are respectively preset maximum and minimum values of the draft depth of the ship, is a three-axis acceleration resultant vector, is a preset maximum acceleration threshold value, is a main shaft speed normalized value, is a rated maximum main shaft speed;

[0016] The comprehensive environment index is calculated based on preset weight coefficients as follows:

[0017] .

[0018] wherein, is a draft depth weight coefficient, is a three-axis acceleration resultant vector weight coefficient, is a main shaft speed weight coefficient. .

[0019] Preferably, the intelligent controller is used for executing special intelligent control, specifically as follows:

[0020] calculating a pressure difference deviation:

[0021] . ​

[0022] wherein, is the pressure difference deviation at the moment; is the set pressure difference, i.e. the target pressure difference to be maintained between the sealed cavity and seawater, is the measured pressure difference between the sealed gas cavity and seawater;

[0023] will be , , converted into the fuzzy language variables of "negative big (NB)", "negative small (NS)", "zero (ZO)", "positive small (PS)", and "positive big (PB)" according to the preset membership function, and the fuzzy set is output through the Mamdani type fuzzy reasoning method according to the fuzzy rule base specially designed for the ship stern shaft sealing system;

[0024] The fuzzy set is converted into the accurate correction amount by using the barycentric method, and the formula of the barycentric method is:

[0025] ;

[0026] wherein, is the accurate output value after defuzzification, is the discrete point of the output universe of discourse, is the discrete point of the output universe of discourse corresponding to the membership degree;

[0027] Real-time correction is performed:

[0028] ;

[0029] wherein, are respectively the proportional coefficient, the integral coefficient, and the differential coefficient of the modified PID controller, are respectively the initial proportional coefficient, the initial integral coefficient, and the initial differential coefficient, are respectively the correction amounts of the proportional coefficient, the integral coefficient, and the differential coefficient;

[0030] The control amount of the final output to the electric control flow regulating valve is calculated:

[0031] ;

[0032] wherein, is the control amount of the output to the electric control flow regulating valve at the moment, is the pressure difference deviation is the integral value from the initial moment to the moment.

[0033] Preferably, the intelligent controller is used to perform the dynamic adjustment function of the flow set value, specifically: ​

[0034] The intelligent controller has a built-in flow setting value mapping table, and calculates the reference flow of the sealing air :

[0035] ;

[0036] wherein, is the reference value under the design working condition, are the water depth compensation coefficient, the acceleration compensation coefficient and the main shaft speed compensation coefficient respectively determined through experiments, and when the dynamic correction amount is introduced when the water depth exceeds a preset threshold value , is the dynamic compensation coefficient;

[0037] The final sealing air flow setting value is .

[0038] Preferably, the intelligent controller is used to perform fault diagnosis and automatic switching functions, and real-time monitoring of the working state of the electric control pressure reducing valve, the flow meter and the electric control flow regulating valve in the active control channel, and when a component jam or signal abnormal fault is detected, the electric control switching valve is driven to switch to the conductive standby safety channel.

[0039] Preferably, the intelligent controller is used to perform a predictive maintenance function, specifically:

[0040] Periodically extract the flow trend slope of the air flow from the system historical data , the standard deviation of the air flow fluctuation , the air flow increment under a specific reference environment index , is the current flow, is the initial flow; Calculate the real-time health index of the sealing ring:

[0041]

[0042] ;

[0043] wherein, is the sealing ring health index at the moment , and are the flow trend slope weight coefficient, the flow fluctuation standard deviation weight coefficient and the flow increment weight coefficient respectively calibrated through experiments, is the initial air flow fluctuation standard deviation of the system, is a preset flow increment failure threshold value;

[0044] By fitting the degradation model of the health index and extrapolating to the failure threshold value, the remaining life is predicted;

[0045] ​The degradation model is:

[0046] ;

[0047] wherein, is the initial health index of the sealing ring; is the degradation rate of the sealing ring;

[0048] Remaining service life is:

[0049] ;

[0050] wherein, is the preset health index failure threshold of the sealing ring.

[0051] Preferably, the intelligent controller is used to perform a pre-warning function when or is lower than the corresponding pre-warning threshold, warning threshold, critical threshold, respectively generates a monitoring prompt, maintenance pre-warning information, and the highest level alarm and switches to the security mode.

[0052] Preferably, an electric control pressure reducing valve output pressure compensation function is used to calculate the output pressure set value of the electric control pressure reducing valve :

[0053] ;

[0054] wherein, is the system demand pressure, is the rated gas source pressure, is the real-time monitored gas source interface pressure, is the gas source pressure compensation coefficient; the intelligent controller is used for feedforward compensation.

[0055] The beneficial effects of the present application are:

[0056] The present application converts sea state disturbance into a feedforward signal through a special fuzzy PID algorithm, realizes the advance compensation of non-linear, lagging disturbance, the pressure control precision fluctuation range is small, and the stability is improved; the present application combines double-channel redundant structure with intelligent fault diagnosis, automatically and seamlessly switches to the standby channel when a fault occurs, ensures uninterrupted sealing gas supply, meets the highest reliability requirements of the ship power system; the integrated valve group of the present application solves the inherent defects of the distributed pipeline, realizes compactness, firmness, low leakage, and easy maintenance; combined with intelligent on-demand control, reduces the wear of the sealing ring, and saves air consumption; the predictive maintenance function of the present application can early warn the sealing ring state, predict the remaining service life, reduce operation and maintenance cost, and improve operation and maintenance efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0057] Figure 1It is a whole structure schematic diagram of the embodiment of the application;

[0058] Figure 2 It is a hardware structure diagram of the double-channel redundant integrated control valve group of the embodiment of the application. DETAILED DESCRIPTION

[0059] The embodiment of the application provides a ship stern shaft sealing self-balancing air control device, as shown in the figure, comprising a double-channel redundant integrated control valve group and a special intelligent control system, the special intelligent control system is electrically connected with the double-channel redundant integrated control valve group. Figure 1

[0060] As shown in the figure, the double-channel redundant integrated control valve group comprises a main block, the main block is made of metal material and is integrally cast or formed by machining, all functional elements are directly installed on the main block, external connecting pipelines are eliminated, the main block is internally provided with a main control channel (A) and a standby safety channel (B) in parallel, the main control channel is sequentially provided with an electric control pressure reducing valve, a flow meter and an electric control flow regulating valve, and the standby safety channel is provided with a mechanical pressure reducing valve and a mechanical flow regulating valve. Figure 2

[0061] The double-channel redundant integrated control valve group further comprises an electric control switching valve and a common converging cavity, an electric control two-position two-way switching valve is adopted in the embodiment, the inlet end of the electric control switching valve is connected with the outlet of the main control channel and the standby safety channel respectively, the outlet end is in communication with the common converging cavity, and the common converging cavity is provided with a pressure sensor and a temperature sensor.

[0062] The double-channel redundant integrated control valve group is provided with a total air inlet path connected with an external air source, the total air inlet path is provided with a pluggable filter element module, and the air filtered by the pluggable filter element module from the external air source is respectively delivered to the main control channel and the standby safety channel; filtered air is provided for the two channels at the same time, so that the cleanliness of the gas is guaranteed.

[0063] The intelligent control system comprises an environment perception module, a data fusion module and an intelligent controller, and the three are linked with each other.

[0064] The environment perception module comprises a draught depth sensor, a three-axis acceleration sensor and a main shaft speed sensor, is used for collecting the draught depth of the ship, the three-axis acceleration resultant vector and the main shaft speed in real time. The three-axis acceleration resultant vector is used for reflecting the degree of heaving of the ship.

[0065] The data fusion module is used for processing the data collected by the environment perception module.

[0066] Normalization processing:

[0067] ;​​

[0068] in, This is the normalized value for draft. , These are the preset maximum and minimum values ​​for the ship's draft. This is the composite vector of triaxial accelerations. This is a preset maximum acceleration threshold; values ​​exceeding this threshold will be treated as the maximum value. Normalized value of spindle speed. This is the rated maximum spindle speed.

[0069] The comprehensive environmental index is calculated based on preset weighting coefficients. :

[0070] ;

[0071] in, This is the draft depth weighting coefficient, used to reflect the impact of the ship's draft on the sealing pressure; The weighting coefficients for the three-axis acceleration synthesis vector are used to reflect the impact of the ship's turbulence on the sealing pressure. The spindle speed weighting coefficient is used to reflect the influence of spindle speed on sealing pressure; In this embodiment, the preferred embodiment is... The comprehensive environmental index quantifies the severity of the current operating environment of a ship. The higher the value, the harsher the environment, and the greater the required baseline value for sealed airflow.

[0072] The intelligent controller is used to perform dedicated intelligent control, dynamic adjustment of flow setpoints, fault diagnosis and automatic switching, and predictive maintenance functions.

[0073] Dedicated intelligent control function refers to the function based on the comprehensive environmental index. and pressure difference deviation Dynamically adjust the parameters (proportional coefficient) of the PID controller. Integral coefficient Differential coefficients This is achieved through a dedicated fuzzy PID control algorithm, specifically:

[0074] Calculate the pressure difference deviation:

[0075] ;

[0076] in, for Pressure difference deviation at any moment; To set the pressure difference, that is, the target pressure difference that needs to be maintained between the sealed cavity and the seawater, this embodiment uses 0.2 bar; The pressure difference between the sealing gas cavity and seawater is measured by a pressure sensor on the common manifold;

[0077] The pressure difference deviation change rate at the moment is:

[0078] .

[0079] Fuzzification: the pressure difference deviation is fuzzified into a fuzzy set of , , According to the preset membership function, it is converted into a fuzzy language variable of "negative big (NB)", "negative small (NS)", "zero (ZO)", "positive small (PS)", and "positive big (PB)";

[0080] Fuzzy reasoning: based on the existing fuzzy rule base specially designed for the stern shaft sealing system of a ship, the Mamdani type fuzzy reasoning method is used to output the fuzzy set of , , .

[0081] Defuzzification: the fuzzy set is converted into an accurate correction amount by using the gravity center method, and the formula of the gravity center method is:

[0082] ;

[0083] wherein, is the accurate output value after defuzzification, i.e. the PID parameter correction amount , is the discrete point of the output universe, is the discrete point of the output universe corresponding to the membership degree.

[0084] The controller uses the accurate correction amount obtained after defuzzification to real-time correct the parameters of the running PID controller according to the following formula:

[0085] ;

[0086] wherein, are the corrected PID controller proportional coefficient, integral coefficient, and differential coefficient, respectively; are the initial proportional coefficient, integral coefficient, and differential coefficient, respectively; are the correction amounts of the proportional coefficient, integral coefficient, and differential coefficient, respectively, which are obtained by the fuzzy reasoning and defuzzification processes;

[0087] After the parameter correction, the controller calculates the control amount of the electric control flow regulating valve according to the following formula:

[0088] ;

[0089] Wherein, is the control amount output to the electric control flow regulating valve at the moment, for adjusting the valve opening; is the pressure difference deviation The integral value from the initial moment to the moment. .

[0090] Drive the electric control flow regulating valve to act, so that stabilize in the range of 0.2bar±0.02bar, realize accurate regulation of air flow.

[0091] The flow setting value dynamic adjustment function of the intelligent controller, the intelligent controller is built-in flow setting value mapping table, the mapping table is established through the existing sea trial data, the reference flow of the sealing air is:

[0092] ;

[0093] Wherein, is the reference value under the design working condition ( ), is the reference value under the design working condition ( ), respectively, the draft depth compensation coefficient, the acceleration compensation coefficient and the main shaft speed compensation coefficient determined through experiment, for example, 5L / min / m can be taken, that is, the reference flow increases by 5L / min when the draft depth increases by 1 meter; when exceeds the threshold value (the threshold value is set to 0.2g in this embodiment), it is considered as severe sea condition, and the dynamic correction amount is introduced, is the dynamic compensation coefficient.

[0094] The control target of the electric control flow regulating valve, that is, the final sealing air flow setting value is .

[0095] The predictive maintenance function of the intelligent controller is specifically:

[0096] Periodically extract the following features from the system historical data: the flow trend slope of air flow (derived by linear regression fitting of the average air flow under the past N stable working conditions), the fluctuation standard deviation of air flow , the air flow increment under the specific reference environment index , is the current flow, is the initial flow.

[0097] The real-time health index of the sealing ring is calculated by using the weighted geometric mean model:

[0098] ; ​

[0099] wherein, is the health index of the seal ring at the moment, are the flow trend slope weight coefficient, the flow fluctuation standard deviation weight coefficient and the flow increment weight coefficient calibrated by experiments respectively, is the initial air flow fluctuation standard deviation of the system, is the preset flow increment failure threshold value, which indicates that the seal ring is severely worn out and needs to be replaced when it exceeds this value.

[0100] Remaining service life prediction: by fitting the degradation model of the health index and extrapolating to the failure threshold, the remaining life is predicted;

[0101] The degradation model is:

[0102] ;

[0103] wherein, is the initial health index of the seal ring; is the degradation rate of the seal ring, which is obtained by fitting historical data.

[0104] Remaining service life is:

[0105] ;

[0106] wherein, is the preset failure threshold of the seal index of the seal ring, below which the seal ring cannot work normally and needs to be replaced immediately;

[0107] Fault prediction performs the following hierarchical warning:

[0108] When or is below the corresponding warning threshold, warning threshold, critical threshold, respectively generates monitoring prompt, maintenance warning information, highest level alarm and switches to security mode.

[0109] The output pressure set value of the electric control pressure reducing valve is fed forwardly compensated by the intelligent controller, and the formula is:

[0110] ;

[0111] wherein, is the system demand pressure, i.e. the actual demand value of the sealing system to the gas pressure, is the rated gas source pressure, is the real-time monitored gas source interface pressure, which is collected by the pressure sensor, is the gas source pressure compensation coefficient. It ensures that even if the gas source pressure fluctuates, the gas pressure entering the flow controller can also remain relatively stable.

[0112] The working principle is:

[0113] The air of the external air source first enters the pluggable filter element module of the total air inlet path, and after filtering and removing impurities, it is simultaneously split into the main control channel and the standby safety channel of the double-channel redundant integrated control valve group. The air output by the two channels is collected to the electric control switching valve, and after being regulated by the switching valve, it is collected into the public collecting cavity, and finally it is uniformly output from the collecting cavity to the ship stern shaft sealing device, forming a complete air supply loop. The environment sensing module collects the working condition data of the ship draft , three-axis acceleration resultant vector , main shaft speed in real time; the data fusion module normalizes the collected data and calculates the comprehensive environment index based on the weight coefficient ; the intelligent controller dynamically adjusts the opening degree of the electric control flow regulating valve according to , pressure difference deviation and its change rate in the active control mode; the intelligent controller diagnoses the system fault in real time, and when detecting the fault of the active control channel, it drives the electric control switching valve to switch to the standby safety channel in milliseconds; the fault prediction unit calculates the sealing ring health index and predicts the remaining service life based on the historical operation data, and performs graded warning.

[0114] The present application is described by way of examples, and those skilled in the art know that various changes or equivalent replacements can be made to these features and examples without departing from the spirit and scope of the present application. In addition, under the guidance of the present application, these features and examples can be modified to adapt to specific conditions and materials without departing from the spirit and scope of the present application. Therefore, the present application is not limited by the specific examples disclosed herein, and all examples falling within the scope of the claims of the present application are within the protection scope of the present application.

Claims

1. A self-balancing air control device for a ship's stern shaft seal, characterized in that, It includes a dual-channel redundant integrated control valve group and a dedicated intelligent control system, wherein the dedicated intelligent control system is electrically connected to the dual-channel redundant integrated control valve group; The dual-channel redundant integrated control valve group includes a main block, an electrically controlled switching valve, a common manifold, and a pluggable filter module. The main block contains an active control channel and a backup safety channel connected in parallel. The active control channel is equipped with an electrically controlled pressure reducing valve, a flow meter, and an electrically controlled flow regulating valve in sequence. The backup safety channel is equipped with a mechanical pressure reducing valve and a mechanical flow regulating valve. The inlet of the electrically controlled switching valve is connected to the outlets of the active control channel and the backup safety channel, respectively, and the outlet is connected to the common manifold. The common manifold is equipped with a pressure sensor and a temperature sensor. The pluggable filter module is located in the main air intake, which is connected to an external air source. Air filtered by the pluggable filter module is delivered to both the active control channel and the backup safety channel. The dedicated intelligent control system includes an environmental sensing module, a data fusion module, and an intelligent controller, which are interconnected. The environmental sensing module includes a draft sensor, a triaxial acceleration sensor, and a spindle speed sensor. The data fusion module is used to process the data collected by the environmental sensing module. The intelligent controller is electrically connected to an electrically controlled pressure reducing valve, an electrically controlled flow regulating valve, an electrically controlled switching valve, a pressure sensor, and a temperature sensor.

2. The ship stern shaft seal self-balancing air control device according to claim 1, characterized in that, The main block is made of metal material and is integrally cast or machined. The electrically controlled switching valve is an electrically controlled two-position two-way switching valve.

3. The ship stern shaft seal self-balancing air control device according to claim 1, characterized in that, The environmental sensing module collects the ship's draft in real time through a draft depth sensor, a triaxial accelerometer, and a spindle speed sensor. Triaxial acceleration composite vector Spindle speed ; The data fusion module processes the data collected by the environmental perception module as follows: Normalization process: ； in, This is the normalized value for draft. , These are the preset maximum and minimum values ​​for the ship's draft. This is the composite vector of triaxial accelerations. To preset the maximum acceleration threshold, Normalized value of spindle speed. This is the rated maximum spindle speed; The comprehensive environmental index is calculated based on preset weighting coefficients. : ； in, For draft depth weighting coefficient, The weighting coefficients are for the synthesis vector of triaxial acceleration. The spindle speed weighting coefficient. .

4. The ship stern shaft seal self-balancing air control device according to claim 1, characterized in that, The intelligent controller is used to perform dedicated intelligent control, specifically: Calculate the pressure difference deviation: ； in, for Pressure difference deviation at any moment; To establish the pressure difference, that is, the target pressure difference that needs to be maintained between the sealed cavity and the seawater, To measure the pressure difference between the sealed air chamber and the seawater; Will , , Based on the preset membership function, it is transformed into fuzzy linguistic variables of "negative large (NB)", "negative small (NS)", "zero (ZO)", "positive small (PS)" and "positive large (PB)", and outputs fuzzy sets through the Mamdani-type fuzzy inference method using a fuzzy rule base designed specifically for ship stern shaft sealing systems. The centroid method is used to transform fuzzy sets into precise correction quantities. The formula for the centroid method is: ； in, To obtain the accurate output value after deblurring, To output discrete points of the universe of discourse, To output discrete points on the universe of discourse Corresponding membership degree; Perform real-time corrections: ； in, These are the proportional coefficient, integral coefficient, and derivative coefficient of the corrected PID controller. These are the initial proportional coefficient, integral coefficient, and differential coefficient, respectively. These are the correction amounts for the proportional coefficient, integral coefficient, and differential coefficient, respectively. Calculate the final control quantity output to the electronically controlled flow regulating valve: ； in, for The control quantity constantly output to the electronically controlled flow regulating valve Pressure difference deviation From the initial moment to The integral value at time step.

5. The ship stern shaft seal self-balancing air control device according to claim 1, characterized in that, The intelligent controller is used to perform dynamic adjustment of the flow setpoint, specifically: The intelligent controller has a built-in flow setpoint mapping table to calculate the reference flow rate of the sealing air. : ； in, For design working conditions ( The baseline value under ) These are the draft compensation coefficient, acceleration compensation coefficient, and spindle speed compensation coefficient, determined experimentally. When the threshold is exceeded, a dynamic correction amount is introduced. , For dynamic compensation coefficients; The final sealing air flow rate setting value is .

6. The ship stern shaft seal self-balancing air control device according to claim 1, characterized in that, The intelligent controller is used to perform fault diagnosis and automatic switching functions, and monitors the working status of the electrically controlled pressure reducing valve, flow meter and electrically controlled flow regulating valve of the active control channel in real time. When a component jamming or abnormal signal fault is detected, it drives the electrically controlled switching valve to switch to the backup safety channel.

7. The self-balancing air control device for ship stern shaft seals according to claim 1, characterized in that, The intelligent controller is used to perform predictive maintenance functions, specifically: Periodically extract the slope of the airflow trend from the system's historical data. Standard deviation of airflow fluctuation Specific benchmark environmental indices airflow increment , For current traffic, This is the initial flow rate; Calculate the real-time health index of the sealing ring: ； in, for The health index of the sealing ring at all times. These are the weighting coefficients for the flow trend slope, the standard deviation of flow fluctuation, and the flow increment, respectively, calibrated through experiments. This represents the initial standard deviation of the airflow fluctuation in the system. The preset threshold for incremental traffic failure; Remaining lifespan is predicted by fitting a degradation model of the health index and extrapolating it to the failure threshold. The degradation model is as follows: ； in, The initial health index of the sealing ring; This refers to the degradation rate of the sealing ring; Remaining service life for: ； in, This is the preset failure threshold for the seal health index.

8. The self-balancing air control device for ship stern shaft seals according to claim 7, characterized in that, The intelligent controller is used to perform an early warning function, when or When the thresholds fall below the corresponding early warning threshold, warning threshold, and critical threshold, a monitoring prompt, maintenance early warning information, and the highest level alarm are generated respectively, and the system switches to security mode.

9. The self-balancing air control device for ship stern shaft seals according to claim 1, characterized in that, The function used to perform output pressure compensation of the electrically controlled pressure reducing valve is to calculate the output pressure setpoint of the electrically controlled pressure reducing valve. : ； in, To meet system demand pressure, Rated air source pressure, For real-time monitoring of the gas source interface pressure, This is the gas source pressure compensation coefficient; it is compensated by the intelligent controller.

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