Underwater Heated Pipe with Parallel Circuits and Sealed Insulation
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Solution Overview
Problem
Existing electric heating solutions for underwater pipes with simple envelopes are inefficient and prone to water invasion, leading to reliability issues and reduced effectiveness in maintaining fluid temperature above critical thresholds.
Innovation Solution
A heating system for underwater pipes comprising a transport tube, an inner electric insulation layer, a sealing tube made of conductive material, and an external thermal insulation layer, with electrical cables connected to form two parallel circuits to heat the transport tube by joule effect, ensuring waterproofing and high heating efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If an alternating electric current is applied directly to the inner steel casing of a single-wall underwater pipeline for heating, then the fluid temperature can be maintained, but strong currents circulate in the surrounding seawater reducing heating effectiveness
Solution Approach 1:
The pipeline is divided into two separate wall layers: an inner transport tube and an outer sealing tube. The electric current is applied to the outer sealing tube instead of the inner transport tube, segmenting the functions of fluid transport and electrical heating. This prevents direct current-induced seawater circulation while maintaining fluid temperature through the sealed outer tube's heating.
Solution Approach 2:
An intermediate layer of electrical insulation is introduced between the inner transport tube and the outer sealing tube. This intermediary layer electrically isolates the inner tube from the seawater, allowing the outer tube to be heated by electric current without inducing harmful currents in the surrounding water, thereby maintaining heating effectiveness.
2Power
If an external grid is used to transport electric current around a single-wall pipeline, then heating can be achieved, but the system is prone to water intrusion and reliability issues
Solution Approach 1:
The outer sealing tube serves dual functions: it acts as both the structural envelope of the pipeline and the conductor for transporting electric current. By merging these two functions into a single component, the need for separate external grids is eliminated, removing the vulnerability to water intrusion associated with external electrical components.
Solution Approach 2:
The outer sealing tube is designed to perform multiple functions simultaneously: providing mechanical protection, maintaining pressure containment, and serving as the electrical conductor for heating. This multi-functionality eliminates the need for separate dedicated electrical grids, improving reliability by reducing potential failure points related to waterproofing.
3Temperature
If thermal insulation is placed directly in contact with seawater in single-wall pipes, then some thermal protection is provided, but heating efficiency is reduced due to heat loss
Solution Approach 1:
The thermal insulation is segmented from direct contact with seawater by positioning it between the inner transport tube and the outer sealing tube. This segmentation creates a protected thermal environment that prevents heat loss to the surrounding water, while still providing necessary thermal protection to maintain fluid temperature.
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
The solution provides a reliable and efficient heating system for underwater pipes, achieving heating efficiency of 85% to 90% and preventing water invasion, thus ensuring uninterrupted fluid transport even in high water depths.
Implementation Method 1
produce two parallel electrical circuits each traversed by an electric current to heat the transport tube of the pipe by the Joule effect
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention concerns a heated underwater pipe (2) for transporting fluids, comprising a plurality of pipe sections each comprising a transport tube (4) intended to receive the fluids, an inner electrical insulation layer (6) disposed around the transport tube, a sealing tube (8) made from an electrically conductive material, disposed around the inner electrical insulation layer, an outer thermal insulation layer (10) disposed around the sealing tube, the transport tube being electrically connected to the sealing tube at each of the two ends of the pipe, the pipe further comprising two electrical cables (16a, 16b) connected to an electrical generator (14) as well as to the transport tube and to the sealing tube of the pipe at a point located between the two ends of the pipe so as to produce two parallel electrical circuits through each of which an electrical current passes in order to heat the transport tube of the pipe by the Joule effect. The invention also concerns a method for assembling such a pipe.