Seal for Cable Anchor Device Maintaining Hermeticity

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Solution Overview

Problem

Existing sealing systems for structural cable anchor devices in construction work, such as bridges, face challenges in maintaining hermeticity due to the movement and vibration of cables with multiple parallel strands, leading to difficulties in filling voids and maintaining the seal without damaging the sealing product during maintenance, and often require exposing the anchor device to external environments to prevent corrosion.

Innovation Solution

Realigning the sealing boundary to an existing hermetic portion, such as the front surface of the anchor device or its protective sheath, to avoid direct contact with the cable strands, using a flexible membrane sleeve that encircles the cable or its protective sheath, ensuring the anchor device remains inside the dehumidified hollow structure while maintaining high hermeticity and ease of maintenance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sealing product is injected between the strands to fill voids, then hermeticity is improved, but maintenance becomes difficult and sealing product is damaged during strand replacement

Engineering Contradiction:
ImprovehermeticityVSAvoidmaintenance
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The sealing product is extracted from the interior of the cable bundle and relocated to the exterior surface. The sealing layer is applied on the outer surface of the sheath or protective covering, completely separating the sealing function from the strand replacement maintenance activity, thereby eliminating damage to sealing product during maintenance while maintaining hermeticity through the external sealing layer

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

A sheath or protective covering is introduced as an intermediary layer between the sealing product and the cable strands. The sealing product is applied on the outer surface of this intermediary layer, which protects the sealing product from damage during strand replacement while still providing hermetic protection when the intermediary layer is intact

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If anchor device is placed outside dehumidified zone, then cable movement is free, but corrosion protection is reduced

Engineering Contradiction:
Improvecable movementVSAvoidcorrosion
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

A flexible sealing layer is applied on the outer surface of the sheath or protective covering, extending along the cable. This flexible film allows the cable to move freely while maintaining the hermetic seal, enabling the anchor device to remain inside the dehumidified zone for corrosion protection without restricting cable movement

Inventive Principle:
Principle #30Flexible shells and thin films

3Reliability

If sealing boundary is extended to center of opening between strands, then hermeticity is improved, but manufacturing complexity increases

Engineering Contradiction:
ImprovehermeticityVSAvoidsealing system implementation
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The sealing application is extracted from the difficult-to-reach interior spaces between strands and relocated to the accessible outer surface of the sheath or protective covering. This allows the sealing boundary to effectively extend to the center of the opening while using simple surface application methods rather than complex injection processes

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of applying sealing product from the inside out (injecting between strands), the sealing is applied from the outside in (on the outer surface). This inversion of the sealing application direction simplifies the manufacturing process while achieving the same hermetic effect of filling the voids between strands

Inventive Principle:
Principle #13The other way round (Inversion)

Data Source

PatentEP2834418B1Seal for cable anchor device of a cable construction
Publication Date: 2020.07.22 SOLETANCHE FREYSSINET SAS
  • EP2834418B1 patent drawingFigure 1
  • EP2834418B1 patent drawingFigure 2~3
  • EP2834418B1 patent drawingFigure 4~5

AI summary

A seal for sealing a cable anchor device (4) to a structural element (1, 3), the cable anchor device (4) being arranged to anchor at least one cable (2) to the structural element (1,3) and having a front surface (15) facing an opening (6) of the structural element, through which front surface the at least one cable (2) extends towards the exterior of the structural element, characterized in that the seal comprises a sleeve (12) which extends from a perimeter of a surface of the structural element including the opening (6) of the structural element to a perimeter of a hermetic portion of the anchored cable (2) comprising at least the front surface (15) of the anchor device (4).