Cable Conductor Seal Using Absorbent Material and Liquid Settable Compound

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Solution Overview

Problem

Existing methods for forming seals in electrical power cables, particularly in flameproof applications, face challenges such as susceptibility to deformation, difficulty in ensuring proper adhesion, and expertise-dependent quality, especially in addressing gaps between conductors and compatibility with polymeric insulation materials.

Innovation Solution

A method involving passing conductors through a body to define a cavity, filling the cavity with an absorbent material, and then pouring a liquid settable material that absorbs and sets to form a seal between and around the conductors, using materials like ethylcyanoacrylate and absorbents like crushed perlite or silica powder to ensure effective adhesion and sealing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If an elastomeric sealing element is used in a cable gland seal, then the seal can be installed and provides initial sealing, but the cable material is susceptible to plastic deformation and creep over time requiring periodic inspection

Engineering Contradiction:
Improveease of installationVSAvoidseal integrity over time
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The sealing system is divided into two functional parts: an elastomeric sealing element for initial sealing and installation ease, and a settable compound for long-term structural stability and gap filling. This segmentation allows each component to optimize its specific function without compromise.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses a composite sealing system combining elastomeric material and settable compound materials with different properties. The elastomer provides flexibility and initial seal, while the settable compound provides rigid structural support and maintains gap sealing over time, creating a composite sealing solution.

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If a settable compound is introduced between cable gland and cable sheath, then radial forces are not applied to the cable, but gaps between adjacent insulated conductors are not addressed and adhesion may be poor

Engineering Contradiction:
Improveno radial deformationVSAvoidseal effectiveness
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The settable compound is selectively applied to specific locations: between the cable gland body and cable sheath for structural support, and additionally into the cavity surrounding conductors for gap sealing. This local quality approach ensures each area receives the appropriate sealing treatment for its specific requirements.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The elastomeric sealing element acts as an intermediary that works in conjunction with the settable compound. It provides initial sealing and maintains contact pressure while the settable compound cures, ensuring proper adhesion and sealing effectiveness between the compound and conductor surfaces.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If conductors are cut back to expose individual insulated conductors and settable compound is pressed into cavity, then gaps between conductors are addressed, but the sealing process is difficult and quality depends on operator expertise

Engineering Contradiction:
Improvegap sealing effectivenessVSAvoidease of application
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The settable compound is changed from a putty-type consistency requiring kneading to a liquid state that flows easily. This parameter change in viscosity transforms the application process from a skill-intensive manual operation to a simple pouring operation, significantly improving ease of application while maintaining reliable gap sealing.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The manual mechanical process of pressing and kneading putty is replaced with a gravity-driven liquid pouring process. This substitution eliminates the need for operator expertise in manual manipulation while ensuring consistent and complete filling of the cavity around conductors.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 simplifies the sealing process, ensures a reliable seal around conductors, and effectively adheres to polymeric insulation materials, addressing deformation and expertise-related issues while maintaining flameproof integrity.

Implementation Method 1

pouring a liquid settable material into the absorbent material within the cavity; and allowing the settable material to be absorbed by the absorbent material and to set

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

the absorbent material is in the form of a powder, granules or fibres; subsequently pouring a liquid settable material into the absorbent material within the cavity

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP2087568B1A method for forming a seal on conductors of an electrical cable
Publication Date: 2018.03.14 PRATLEY INVESTMENTS
  • EP2087568B1 patent drawingFigure 1
  • EP2087568B1 patent drawingFigure 2

AI summary

The invention provides a method of forming a seal (62) between and around conductors (12A, 12B and 12C) of an electrical power cable (10), and has particular application as a safety measure in potentially explosive applications. The method includes passing the conductors (12A, 12B and 12C) through an opening in a body (26) so as to define a cavity within the body (26) between and around the conductors (12A, 12B and 12C); introducing an absorbent material (64) into the cavity; introducing a liquid settable material (66) into the cavity; and allowing the settable material (66) to be absorbed by the absorbent material (64) and to set thereby to seal the cavity between and around the conductors (12A, 12B and 12C).