Autonomous Underwater Vehicle with Deployable Cathodic Probes
Solution Overview
Problem
Current methods for inspecting subsea hydrocarbon pipelines for corrosion are time-consuming, expensive, and require complex equipment, with remotely operated vehicles (ROVs) operating at slow speeds due to drag issues when using articulated arms with proximity cathodic protection probes.
Innovation Solution
An autonomous underwater vehicle with a lower proximity sensor deployable below the support body and an upper remote sensor with a fish and flexible line, allowing the vehicle to cruise autonomously above the subsea structure at high speeds without contact, using a control unit to maintain probes at fixed altitudes and measure potential differences between cathodic protection probes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a cart rolls on the pipeline to carry the proximity probe, then the probe can be positioned close to the pipe for measurement, but the cart creates strong drag and high friction on the pipeline, limiting the inspection apparatus to very slow speeds
Solution Approach 1:
The invention extracts the harmful rolling contact function from the measurement system. Instead of using a cart that rolls on the pipeline, the proximity probe is mounted on a retractable arm that can extend and retract without contacting the pipe. This separates the measurement function from the harmful mechanical contact, allowing high-speed inspection while maintaining measurement capability.
Solution Approach 2:
The invention makes the probe mounting system dynamic through a retractable arm mechanism. The arm can extend to position the probe close to the pipeline for accurate measurements and retract to minimize drag during high-speed cruise. This dynamic adjustment resolves the contradiction between needing close proximity for measurement and needing to minimize contact for speed.
2Measurement precision
If a cart rolls on the pipeline, then the proximity probe can be maintained close to the pipe surface, but the friction generated creates a substantial risk of damaging the pipeline surface
Solution Approach 1:
The invention removes the harmful rolling contact element (cart) from the system entirely. The proximity probe is instead mounted on a retractable arm that can extend close to the pipe without mechanical contact, eliminating the friction and damage risk while preserving the ability to obtain precise corrosion measurements through non-contact proximity sensing.
Solution Approach 2:
The retractable arm serves as an intermediary between the inspection apparatus and the pipeline. It allows the probe to be positioned close to the pipe for accurate measurements while preventing direct contact between the apparatus and the pipeline surface, thus eliminating the damage risk associated with rolling carts.
3Measurement precision
If traditional ROV methods with articulated arms are used, then corrosion inspection can be performed, but the equipment complexity and operational costs increase significantly
Solution Approach 1:
The invention extracts only the essential measurement function from the complex ROV system. Instead of using a full ROV with articulated arms and surface facility connections, the patent employs a simplified autonomous vehicle with a retractable probe arm, eliminating unnecessary complexity while maintaining corrosion inspection capability.
Solution Approach 2:
The inspection apparatus is designed to be autonomous, serving itself without requiring surface facility support or complex control systems. The vehicle can independently navigate, deploy its probe, perform measurements, and return, eliminating the need for complex ROV infrastructure and reducing operational costs.
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
Enables efficient and cost-effective corrosion inspection of subsea structures at higher speeds than traditional methods, reducing the risk of damaging the pipeline and eliminating the need for surface installations, thus simplifying operations and lowering costs.
Implementation Method 1
the lower proximity sensor comprising a lower cathodic protection probe, the lower proximity sensor being deployable between a retracted position and a deployed position; an upper remote sensor deployable from the support body, comprising an upper cathodic protection probe
Data Source
AI summary
The vehicle includes a support body, able to move along the subsea structure in a body of water, a lower proximity sensor, deployable from the support body towards the subsea structure, the lower proximity sensor comprising a lower cathodic protection probe, the lower proximity sensor being deployable between a retracted position and a deployed position. It also comprises an upper remote sensor deployable from the support body, comprising an upper cathodic protection probe. The lower proximity sensor is located below the support body in the retracted position and in the deployed position.