Modulated Current for Cathodic Protection and Pipe Location
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Solution Overview
Problem
Existing methods for corrosion protection and location of metallic structures, such as pipes buried underground, face challenges in accurately determining the effectiveness of cathodic protection and locating these structures due to limitations in current monitoring and mapping techniques.
Innovation Solution
A remote-controlled modulator unit is integrated with a transformer rectifier unit to produce a modulated current that includes both AC and DC components, enabling wireless detection and location of metallic structures, while also monitoring the cathodic protection system and sending alarms and status reports.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If an AC signal is applied to a buried metallic structure for location purposes, then the structure becomes detectable by electromagnetic locating devices, but the applied current may no longer provide effective cathodic protection
Solution Approach 1:
The patent applies periodic modulation to the DC cathodic protection current, switching it on and off at specific intervals. This creates an interrupted current pattern that serves dual purposes: the DC component maintains cathodic protection when on, while the interruption pattern enables detection and location of the buried structure through electromagnetic field variations, resolving the contradiction between protectiveness and detectability
Solution Approach 2:
The patent changes the temporal parameters of the applied current by introducing periodic interruptions to the DC flow. This parameter modification allows the same current system to fulfill both protective and detection functions, eliminating the need for separate AC signaling systems that would compromise cathodic protection effectiveness
2Measurement precision
If measurement devices are connected directly to the pipe for potential measurements, then cathodic protection effectiveness can be determined, but the process requires manual intervention and is time-consuming
Solution Approach 1:
The patent incorporates remote monitoring capabilities that automatically measure potential and current patterns at the buried structure and provide feedback to surface equipment. This automated feedback system continuously monitors cathodic protection effectiveness without requiring manual device connection and measurement, reducing time loss while maintaining measurement precision
Solution Approach 2:
The system enables self-monitoring of cathodic protection parameters through the modulated current signal itself. The interrupted current pattern and resulting electromagnetic field variations provide inherent information about protection effectiveness that can be detected and analyzed automatically, eliminating the need for separate manual measurement procedures
3Loss of information
If interrupted DC current patterns are used to identify pipelines, then specific pipeline location can be verified, but the process requires physical connection to the pipe and manual analysis
Solution Approach 1:
The patent replaces the mechanical connection requirement with electromagnetic field-based detection. By modulating the DC current and detecting the resulting electromagnetic field variations using wireless or remote sensing equipment, the system identifies and locates pipelines without requiring physical connection to the pipe, significantly improving ease of operation while maintaining identification accuracy
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution allows for effective cathodic protection, accurate location of buried structures, and remote monitoring of cathodic protection levels, reducing the risk of accidental damage during excavation and improving the efficiency of corrosion protection systems.
Implementation Method 1
a transformer rectifier unit operable to output a DC current for cathodic protection of a metallic structure
Implementation Method 2
the modulator unit is operable to produce a modulated current which is applied to such a metallic structure when the apparatus is in use, such that the metallic structure is detectable by a wireless locating device
Data Source
AI summary
Apparatus for connection to a metallic structure, the apparatus comprises a transformer rectifier unit operable to output a DC current for cathodic protection of a metallic structure, and a modulator unit connected to receive a DC output from the transformer rectifier unit. The modulator unit is arranged for connection to a metallic structure, and is operable to produce a modulated current which is applied to such a metallic structure when the apparatus is in use, such that the metallic structure is detectable by a wireless locating device. The modulator unit is operable to be controlled remotely.