Buoyancy-Assisted Cable Laying in Empty Conduits
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Solution Overview
Problem
Current methods for laying high and extra-high voltage cables are inefficient due to heavy cable weights, leading to increased environmental and licensing difficulties, and lack effective solutions for managing heat generated during transmission, which can cause damage to cables.
Innovation Solution
A buoyancy-assisted method for laying cables using a multifunctional empty pipe transport system, where the cable is supported by a payload transport pipe string with a buoyancy medium, allowing for low-friction and reversible insertion and extraction, enabling flexible and safe laying of heavy cables over long distances without extensive construction measures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If cables are laid with larger cross-sections to reduce transmission loss, then electricity transport efficiency is improved, but cable weight increases making laying more difficult
Solution Approach 1:
The patent uses buoyancy as a counteracting force to offset cable weight during laying operations. A buoyancy device is attached to the cable, and air or other gases are introduced to create upward buoyant force that counterbalances the downward gravitational force on the heavy cable, enabling easier handling and laying of large cross-section cables without increasing transmission loss
2Ease of manufacture
If overhead line concepts are used to reduce cable weight impact, then laying difficulty is reduced, but environmental and licensing difficulties increase
Solution Approach 1:
The patent introduces an intermediary buoyancy device that enables underground cable laying without requiring heavy steel reinforcement typically needed for overhead lines. This intermediary solution allows cables to be laid underground with reduced weight requirements, avoiding the environmental and licensing issues of overhead lines while maintaining laying ease
3Strength
If steel reinforcement is added to cables to absorb tensile forces, then cable strength is improved, but cable weight increases further
Solution Approach 1:
The buoyancy device provides upward force that counteracts both the weight and reduces the effective tensile load on the cable during laying. This allows the cable to be laid without heavy steel reinforcement, as the buoyancy support absorbs part of the mechanical stress, enabling the use of lighter cable constructions
4Ease of operation
If heavy cables are pulled into empty conduits using traditional methods, then cable installation is achieved, but friction and laying difficulty increase significantly
Solution Approach 1:
The buoyancy device attached to the cable creates upward force that counteracts the cable weight, significantly reducing the normal force between the cable and conduit walls during pulling operations. This reduction in normal force directly decreases friction force, enabling heavy cables to be pulled into long conduits with much reduced laying difficulty
Solution Approach 2:
The patent uses pneumatic systems to introduce air or other gases into the buoyancy device, creating the buoyant force needed to offset cable weight. This pneumatic mechanism enables controlled adjustment of buoyancy during the cable pulling process, facilitating easier installation by reducing friction forces
5Ease of operation
If buoyancy material is used to support cables during laying, then laying difficulty is reduced, but heat accumulation in cable insulation increases
Solution Approach 1:
The patent separates the buoyancy function from the cable insulation by using an external buoyancy device attached to the cable rather than embedding buoyancy material within the insulation. This extraction of the buoyancy function allows the cable insulation to remain thermally conductive without harmful heat accumulation, while still achieving reduced laying difficulty through external buoyant support
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 method reduces cable weight and friction during laying, allows for flexible and reversible cable installation, and utilizes buoyancy to manage heat, enhancing the efficiency and safety of cable laying while reducing costs and environmental impact.
Implementation Method 1
the cable is supported by a payload transport pipe string with a buoyancy medium, allowing for low-friction and reversible insertion and extraction
Implementation Method 2
Active cooling of cables with gaseous or liquid cooling media
Implementation Method 3
utilizes buoyancy to manage heat, enhancing the efficiency and safety of cable laying
Data Source
Figure 1a~3c
Figure 4a~4e
Figure 5a~5b
AI summary
The present invention relates to a method for the active cooling of cables with gaseous or liquid cooling media, in which the cables are mounted or laid by means of buoyancy support, wherein a) at least one empty conduit (1) is laid or provided, the inner diameter (d1) of which is larger than the outer diameter (d2) of a payload transport pipe string (2); and b) at least one high-point head station (20, 20a) and at least one low-point head station (30) are erected or provided in the area of the empty conduit route and access points in an empty conduit system are provided in this way;and c) at least one active feed system is provided and at least one payload transport pipe string (2) is pre-assembled outside the empty pipe (1), which fulfills the function of a carrier pipe in which the cable (3) to be laid or the payload to be laid is placed and thus a payload transport pipe system is created which, when it has subsequently been tightly sealed, fulfills the requirement of low-friction and low-resistance laying in the empty pipe (1) flooded with at least one buoyancy medium (23) due to buoyancy;and d) with the aid of the active feed system, the payload transport pipe string (2) is introduced via the high-point head station (20, 20a) and transported and positioned up to a low-point head station (30) at the destination within the empty pipe system, and for this purpose the empty pipe system is flooded by the use of at least one primary buoyancy medium (23), wherein the payload transport pipe string (2) is matched in its outer diameter (d2) to the necessary and desired effective buoyancy (A), which acts in the buoyancy medium (23) of known density on the payload transport pipe string (2) closed for this purpose, in order to counteract the respective weight (G) of the payload transport pipe string (2) during transport and positioning of the payload transport pipe string (2) within the empty pipe system, wherein the density of the buoyancy medium (23) can be changed by additions or exchanges and thus the buoyancy behavior can also be changed during the assembly process.