Intumescent Coated Bellows for Articulated Vehicle Fire Resistance

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Solution Overview

Problem

Existing bellows designs for articulated vehicles, particularly those made of aluminum, face high thermal loads during fires, leading to melting and structural collapse, which exposes the transition floor to direct flames and exceeds permissible surface temperatures quickly.

Innovation Solution

Applying a heat-expanding fire protection coating to the bellows frames and middle frames, along with a support profile, to create a thermal barrier that delays heat exposure and maintains structural integrity by forming an ash skeleton under pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If aluminum bellows frames are used for articulated vehicles, then the frames are lightweight and have good structural properties, but they melt and collapse under high thermal loads during fires, exposing the transition floor to direct flames

Engineering Contradiction:
Improveweight of bellows framesVSAvoidfire resistance of bellows frames
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The patent applies a fire protection coating made of intumescent material to the aluminum bellows frames, creating a composite structure that combines the lightweight properties of aluminum with the fire-resistant properties of the coating. This composite approach allows the frames to maintain both low weight and high fire resistance, resolving the contradiction between lightweight construction and fire reliability.

Inventive Principle:
Principle #40Composite materials

2Reliability

If the bellows structure is exposed to direct flames, then the thermal protection is immediately compromised, but adding fire protection measures increases device complexity

Engineering Contradiction:
Improvethermal protection durationVSAvoidcomplexity of fire protection system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The fire protection coating is designed to be self-activating through its intumescent properties. When exposed to heat, the coating automatically expands and forms an insulating carbonaceous layer without requiring external activation mechanisms, sensors, or control systems. This self-service approach provides reliable thermal protection while minimizing device complexity.

Inventive Principle:
Principle #25Self-service

3Strength

If a fire protection coating is applied to the bellows frames, then the thermal stress on the bellows is reduced and structural integrity is maintained, but the coating adds weight and complexity to the frames

Engineering Contradiction:
Improvestructural integrity of bellows framesVSAvoidweight of bellows frames with coating
Core Design Contradiction:
StrengthVSWeight of stationary object

Solution Approach 1:

The fire protection coating undergoes parameter changes when exposed to heat, transforming from a thin coating to an expanded insulating structure. This allows the coating to provide substantial thermal protection with minimal initial material thickness and weight, maintaining structural integrity while minimizing weight increase.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If the bellows frames are made thicker to resist thermal loads, then fire resistance improves, but the weight and manufacturing complexity increase significantly

Engineering Contradiction:
Improvefire resistance of bellows framesVSAvoidmanufacturing ease of bellows frames
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Instead of increasing the thickness of the aluminum frames themselves, the patent extracts the fire protection function into a separate coating layer. This allows the frames to remain thin and easy to manufacture while the coating provides the necessary fire resistance, separating the structural function from the fire protection function.

Inventive Principle:
Principle #2Taking out (Extraction)

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

Significantly reduces thermal stress on the bellows, preserving the thermal protection for a longer period and preventing surface temperature exceedance, thus enhancing fire resistance and maintaining the structural integrity of the bellows.

Implementation Method 1

a fire protection coating, with the fire protection coating being designed as a material that expands under the action of heat

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

the fire protection coating being designed as a material that expands under the action of heat, in particular as a material that expands under pressure

Methodology Applied
Scientific EffectIntumescent material expansion: Intumescent Materials

Implementation Method 3

forming an ash skeleton under pressure... which not only prevents direct flame impingement of the bellows frame over a certain period of time

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP3228484B1Bellows for the transition between two vehicles with a jointed connection
Publication Date: 2019.12.11 HUBNER GMBH
  • EP3228484B1 patent drawingFigure 1~2
  • EP3228484B1 patent drawingFigure 3~4
  • EP3228484B1 patent drawingFigure 5

AI summary

The invention relates to a bellows (10) of a transition (5) between two articulated vehicle parts (2, 3), wherein the bellows (10) has at least one frame device, wherein the frame device is at least partially flame-retardant.