Corrosion Monitoring System for the Outer Wall of Steel-Encased Immersed Tunnel Sections
System Composition
Sacrificial Anode Current Monitoring System
Working Principle
◆ The sacrificial anode leg is cut off and insulated;
◆ The protective current between the sacrificial anode and the steel hull is transmitted via lead wires, with the anode current transmitter connected in series within the circuit;
◆ The anode current transmitter measures the protective current intensity, thereby enabling monitoring of the sacrificial anode’s current output.
◆ Signals acquired by each current transmitter are centrally transmitted to the CP monitor for data storage, transmission, analysis, and other functions.
◆ Data is uploaded to the central control computer for evaluation of the sacrificial anode consumption rate and remaining service life.
▎Technical Specifications of the Sacrificial Anode Current Monitoring System
▎Schematic Diagram of the Sacrificial Anode Current Monitoring System
Steel Shell Thickness Inspection System
Working Principle
◆ Ultrasonic pulses generated by the ultrasonic transducer propagate through the couplant and reach the test specimen;
◆ When ultrasonic pulses propagate through the test object and reach the material interface, a portion of the ultrasonic signal is reflected from the bottom surface of the object. By measuring the round-trip travel time of the ultrasonic wave in the material, the thickness value can be calculated.
▎Technical Specifications of the Steel Hull Thickness Monitoring System
▎Schematic Diagram of the Steel Shell Thickness Monitoring System
Steel Structure Surface Potential Monitoring System
Working Principle
◆ The reference electrode is installed at various locations on the steel structure to monitor the surface potential at representative points.
◆ The potential signals acquired by each reference standalone unit are centrally transmitted to the CP monitor for data storage, transmission, analysis, and other functions.
◆ The potential data measured by the monitoring instrument are transmitted to the host computer via the RS485 communication bus;
◆ The computer processes the potential data from each monitoring point, displays the potential measurement curves, and saves the potential data to the database;
◆ Monitor the protective potential of the external surface of underwater structures to assess the status of corrosion protection.
▎Technical Specifications of the Composite Reference Electrode
▎Schematic Diagram of the Steel Hull Surface Potential Monitoring System
Steel Structure Surface Current Density Monitoring System
Background
◆ As the protective coating ages, the insulation resistance decreases, leading to a continuous increase in the protection current density, which gradually rises from its initial minimum value.
◆ The cathodic protection status of the steel shell and the extent of coating damage can be assessed by monitoring the current density on the steel shell surface.
▎Schematic Diagram of the Steel Shell Surface Current Density Monitoring System
Working Principle
◆ The test specimen to be monitored is installed on the exterior of the steel shell, with the instrument material and coating being identical to those of the monitored steel shell;
◆ The current intensity released by the test specimen into the seawater is monitored, and the current density of the monitored cathodic test specimen is calculated using the formula: “Current density = Measured current intensity / Immersed surface area of the test specimen.”
▎Technical Specifications for Steel-Hull Surface Current Density Monitoring Sensors
Steel Hull Surface Coating Impedance Monitoring System
Structural form
◆ The coating impedance monitoring system is based on electrochemical impedance spectroscopy (EIS) and employs a conventional three-electrode configuration, consisting of a working electrode, a counter electrode, and a reference electrode.
Working Principle
◆ The reference electrode is installed at different locations on the steel shell to monitor the surface potential at typical positions;
◆ The potential signals acquired by each reference electrode are centrally transmitted to the CP monitoring instrument for data storage, transmission, and analysis;
◆ The potential data measured by the monitoring instrument are transmitted to the host computer via the RS485 communication bus;
◆ The computer processes the potential data from each monitoring point, displays the potential measurement curves, and saves the potential data to the database;
◆ Evaluate the corrosion protection condition based on the protective potential of the steel hull’s external surface.
▎Technical Specifications of Coating Impedance Monitoring Probe
▎Schematic Diagram of the Steel Hull Surface Coating Impedance Monitoring System
Software – Corrosion Protection Monitoring and Assessment System Based on Multi-Data Fusion
Main Functions
♦ Real-time monitoring and display of parameters such as steel shell potential, sacrificial anode current, remaining service life of sacrificial anodes, coating impedance, and coating condition;
♦ Highly automated data acquisition, analysis, fault alarm, over/under protection pre-warning, and probe leakage alarm, among others;
♦ Enables querying and analysis of historical data and logs, with automatic generation of formatted reports and statements;
♦ Visualize the protection status and alert to areas that may be under-protected or over-protected;
♦ Multi-terminal remote access, centralized control via a central control system, and shore-based remote control; technical experts can provide remote diagnostics.
Contact Information
Address: Company Headquarters:Building A, Overseas Students’ Entrepreneurship Park, No. 1 Huoju Road, High-tech Industrial Park, Dalian
Experiment–Manufacturing Base: Tangli Industrial Park, Hongqi Subdistrict, Ganjingzi District, Dalian City
Telephone: Corporate Headquarters: 0411-84660668
Experiment-Manufacturing Base: 0411-82646110
Email: info@kingmile.com
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