Flexible Fire-Resistant Conduit Liner with Heat-Expandable Seals

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Solution Overview

Problem

Existing conduit protection devices are expensive, heavy, and limited in adaptability, failing to effectively protect internal distribution elements from fire spread and foreign intrusions due to their rigid design and pre-defined dimensions, leaving inner conduit areas unprotected.

Innovation Solution

A flexible, closed bag-like container with heat expandable strips made of glass fiber, graphite, or their combination, which surrounds distribution elements inside conduits, expanding to create a compact seal and prevent fire and smoke spread, while also allowing for easy installation and adaptability to various conduit sizes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If rigid metallic collar devices are used to protect conduits, then protection against foreign elements is provided, but adaptability to different conduit sizes and sections is limited

Engineering Contradiction:

Improveprotection against foreign elementsVSAvoidadaptability to different conduit sizes

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent employs a flexible bag made of heat-expandable material that can be inserted into conduits of various sizes and shapes. This flexible structure adapts to different conduit configurations while providing fire protection, eliminating the size limitations of rigid metallic collars.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The flexible bag changes its physical parameters (volume, shape, density) in response to temperature changes. At normal temperatures, it remains compact for easy insertion, but when exposed to fire, it expands to fill the conduit space, providing effective fire containment across different conduit sizes.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If solid metallic bodies with elastomeric parts are used, then conduit protection is achieved, but device weight and cost increase

Engineering Contradiction:

Improveconduit protectionVSAvoiddevice weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The flexible bag is designed as a lightweight, single-use fire protection device that can be easily installed and discarded after use, eliminating the need for heavy, expensive metallic structures with multiple components like screws, nuts, and washers.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent replaces the mechanical fastening system (screws, nuts, washers, rigid bodies) with a simple insertion-based flexible bag that relies on heat expansion for its protective function, significantly reducing weight and complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If pre-defined dimensional collars are used, then manufacturing is simplified, but ability to protect inner conduit areas with distribution elements is reduced

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidprotection of inner conduit areas

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The flexible bag can be inserted into the conduit and expanded to surround distribution elements within the conduit, providing protection to inner areas that rigid collars cannot reach due to their fixed dimensions and external placement requirements.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The flexible bag is designed to be inserted into the conduit and can envelop distribution elements (cables, pipes) within it, creating a nested configuration where the protective bag contains both the conduit and its internal elements, ensuring comprehensive fire protection.

Inventive Principle:

Principle #7Nested doll (Nesting)

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 flexible container provides comprehensive protection against fire and foreign elements, ensuring effective containment of fire and smoke within conduits, regardless of fire origin, and is cost-effective and easy to install, addressing the limitations of existing solutions.

Implementation Method 1

at least two strips (4) of a heat expandable material (increases in volume) each arranged in the proximity and parallel to two first sides (5, 5') of the flexible container (3)

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP3757436B1Device for preventing the spread of fire

Publication Date: 2022.05.11 MARTRA PATENT BOX SL

Figure 1~2

AI summary

Device for preventing the spread of fire comprising two opposite faces each with four sides, the two faces being joined along said four sides and at least two strips (4) of a heat expandable material, each arranged in the proximity and parallel to two first sides (5, 5') of the flexible container (3) opposite each other of. The thickness of each of said at least two strips (4) is comprised between 2.5 ±1 mm. As a result of the flexibility thereof, the container is suitable for being arranged around the distribution elements housed inside a conduit, enclosing them, such that it protects both the conduit and the distribution elements therein from fire and the entry of unwanted elements.