Fire Damper Bearing Layout for Continuous Thermal Sealing

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Solution Overview

Problem

Existing fire dampers have weight imbalances and structural weaknesses at bearing points, leading to interrupted thermal seals and reduced sealing effectiveness during fires.

Innovation Solution

The fire damper design features offset bearing pins relative to the damper blade's median plane, ensuring a continuous thermal seal and balanced weight distribution without recesses in the end face, allowing uninterrupted thermal expansion to seal the gap between the damper blade and housing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If bearing pins are arranged symmetrically on the median plane of the damper blade, then the mounting is simplified and weight balance is achieved, but the thermal seal is interrupted at the bearing points reducing sealing effectiveness

Engineering Contradiction:
Improvemounting simplicityVSAvoidsealing effectiveness
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies asymmetry by offsetting the bearing pins from the median plane of the damper blade. Instead of symmetric arrangement, the bearing pins are positioned at different distances (A1 and A2) from the median plane, creating an asymmetric configuration that allows the thermal seal to remain continuous and uninterrupted while still providing proper mounting support.

Inventive Principle:
Principle #4Asymmetry

2Ease of manufacture

If recesses are provided in the end face of the damper blade for mounting bearing pins, then the bearing pins can be securely attached, but the structural integrity of the damper blade is weakened

Engineering Contradiction:
Improvebearing pin attachmentVSAvoidstructural integrity
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent extracts the recesses from the end face of the damper blade. Instead of providing recesses in the end face for mounting bearing pins, the design eliminates these recesses entirely and uses an alternative mounting approach that maintains structural integrity while still allowing secure attachment of bearing pins.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If the thermal seal is wrapped around bearing points on both sides, then the bearing points are sealed, but the thermal seal material is interrupted and narrowed leaving insufficient material for expansion during fire

Engineering Contradiction:
Improvebearing point sealingVSAvoidthermal seal material availability
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The asymmetric offset of bearing pins from the median plane allows the thermal seal to be positioned continuously along the circumferential end face without being interrupted or narrowed by bearing points. This configuration ensures sufficient thermal seal material remains available for expansion during fire conditions while still providing adequate sealing.

Inventive Principle:
Principle #4Asymmetry

4Device complexity

If bearing pins are positioned close to the circumferential edge of the damper blade end face, then the mounting is compact, but the thermal seal is located in a constrained area reducing expansion capability

Engineering Contradiction:
Improvemounting compactnessVSAvoidthermal expansion capability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

By offsetting bearing pins asymmetrically from the median plane rather than positioning them symmetrically close to the circumferential edge, the design creates sufficient space for the thermal seal to expand freely during fire conditions while maintaining a compact overall mounting configuration.

Inventive Principle:
Principle #4Asymmetry

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 design provides a well-balanced, structurally intact damper blade with effective sealing capabilities, ensuring a tight seal across the entire front face during a fire by maintaining a continuous thermal seal and allowing easy movement of the damper blade.

Implementation Method 1

at least one thermal seal made of a material which expands when exposed to heat

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP4279146B9Fire damper
Publication Date: 2025.12.24 TROX SE
  • EP4279146B9 patent drawingFigure 1~3
  • EP4279146B9 patent drawingFigure 4~8
  • EP4279146B9 patent drawingFigure 9~12

AI summary

The invention relates to a fire damper with a housing having a housing wall, preferably having a round or a square flow cross-section, and with a damper blade, preferably made of calcium silicate and having a thickness D, pivotably mounted therein, preferably centrally on the flow cross-section, between an open position and a closed position about an axis of rotation, wherein the damper blade has two opposing damper blade surfaces connected by a circumferential end face, and wherein the fire damper has two centrally opposing bearing points, forming the axis of rotation and relating to the flow cross-section, for mounting the damper blade, and wherein at least one bearing point is formed on the one hand by a receptacle provided in the housing, preferably designed as a recess, and on the other hand by a bearing pin.wherein the bearing pin is connected to the damper blade at one end, and projects into the corresponding receptacle at the other end, which projects away from the end face of the damper blade, and wherein the fire damper further comprises at least one thermal seal made of a material that expands when exposed to heat, wherein the at least one thermal seal is provided on the circumferential end face of the damper blade, wherein, in the closed state of the damper blade, a circumferential movement gap is provided between the inside of the housing and the thermal seal, which has not yet expanded due to heat, and/or, at least in the part extending along the circumference of the damper blade in the closed state, a movement gap is provided on the inside of the housing, wherein, in the closed state of the damper blade, between the end face of the damper blade and the thermal seal,which has not yet expanded due to heat exposure, a circumferential movement gap is provided. In order to specify a fire damper that is well-balanced in terms of weight, that has good structural integrity of the damper blade in the area of ​​the two bearing points, and that also has a good seal in the event of a fire, the bearing pins are to be arranged offset from each other with respect to the central plane M of the damper blade, which extends parallel to the two damper blade surfaces, wherein one bearing pin is arranged offset by a distance A1 in the direction of one damper blade surface to the central plane M, and the other bearing pin is arranged offset by a distance A2 in the direction of the other damper blade surface to the central plane M.where distance A1 is understood to be the distance between the median plane M and the center point of one bearing pin, and distance A2 is understood to be the distance between the median plane M and the center point of the other bearing pin, and where the centers of the two supports are arranged at a distance A in the direction of flow, which results from the sum of the distances A1 + A2.