Cable Bushing Dual Membrane Seal for Ceiling Watertightness

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Solution Overview

Problem

Existing cable bushings fail to achieve absolute internal tightness, particularly in ceiling installations, allowing liquids to pass through and leading to moisture issues and mold growth.

Innovation Solution

A second ring-shaped, membrane-like sealing element is added to the cladding tube, combined with a rigid annular body made of hard plastic, ensuring almost absolute tightness and preventing moisture ingress by forming a module that can be easily attached and fixed, using a rubber-elastic material for optimal sealing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single sealing element is used in the cable bushing, then the device complexity is low and ease of manufacture is high, but the watertightness and reliability are insufficient allowing liquid penetration

Engineering Contradiction:
ImprovewatertightnessVSAvoidsealing structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The sealing structure is divided into two distinct sealing elements: a first sealing element at one end of the cladding tube and a second sealing element at the other end. This segmentation allows each sealing element to independently perform its sealing function, ensuring watertightness at both ends of the cable bushing and preventing liquid penetration along the cable path.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sealing solution transitions from a single-point sealing approach to a multi-dimensional sealing strategy by adding sealing elements at both axial ends of the cladding tube. This dimensional expansion of the sealing architecture ensures comprehensive coverage and eliminates pathways for liquid infiltration.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If a rigid annular body with membrane-like sealing element is added to the cladding tube, then the watertightness is significantly improved, but the device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improveinternal tightnessVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The enhanced sealing system is divided into modular components: a rigid annular body structure and membrane-like sealing elements that can be separately manufactured and then assembled. This segmentation enables independent optimization of each component's manufacturing process while simplifying the overall assembly procedure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sealing system combines rigid annular body material with flexible membrane-like sealing material to create a composite structure. This composite approach leverages the strengths of both material types: the rigid body provides structural support and positioning, while the membrane-like material provides flexible sealing contact with the cable, achieving superior tightness.

Inventive Principle:
Principle #40Composite materials

3Adaptability or versatility

If the sealing element is made from rubber-elastic material, then the sealing performance and adaptability to cable dimensions are improved, but the mechanical strength and durability may be reduced

Engineering Contradiction:
Improvesealing adaptabilityVSAvoidmechanical strength
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The sealing system employs a composite structure combining rigid annular body material with flexible rubber-elastic membrane-like sealing elements. The rigid body provides mechanical strength and structural integrity, while the rubber-elastic membrane provides adaptability and sealing contact, allowing the system to achieve both strength and versatility simultaneously.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

Different parts of the sealing structure have different material properties optimized for their specific functions: the rigid annular body provides structural support and positioning where strength is needed, while the membrane-like sealing elements are made of rubber-elastic material where flexibility and adaptability are required for effective sealing contact with the cable.

Inventive Principle:
Principle #3Local quality

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 enhanced watertightness and prevents mold growth by ensuring a tight seal, even in ceiling ducts, maintaining fire protection functionality and mechanical stability throughout the service life.

Implementation Method 1

The membrane-like sealing element consists of a rubber-elastic material

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The sealant is an intumescent mass that expands in the event of a fire and closes the lead-through opening

Methodology Applied
Scientific EffectIntumescent expansion: Intumescent Materials

Data Source

PatentEP2806199B1Cable bushing
Publication Date: 2019.01.09 HILTI AG
  • EP2806199B1 patent drawingFigure 1
  • EP2806199B1 patent drawingFigure 2

AI summary

The invention relates to a cable penetration (10) for passing cables through a component (30), comprising a casing (11), a base part (16) arranged at a first axial end (12) of the casing (11), which has a receiving chamber (18) surrounding a penetration opening (17) for a firestop (19), an annular, membrane-like sealing element (14) arranged at the first axial end (12) of the casing (11), and a further membrane-like sealing element (15) arranged at the second axial end (13) of the casing (11) of the cable penetration (10). A firestop (19) is arranged in the receiving chamber (18), thereby ensuring fire protection of the cable penetration (10).