Offset-Axis Fire Damper with Fusible Release to Prevent Jamming

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Solution Overview

Problem

Offset-axis fire dampers are not normally reversible and can deform or jam when a fire starts on the side of the operating axis, compromising their ability to create a fire-tight barrier.

Innovation Solution

An operating device for a butterfly damper with an offset axis that includes a fusible element to secure the mounting bracket and a locking device to maintain the damper in the closed position, along with a temperature sensor to control the motor and prevent deformation, ensuring the damper remains closed during a fire.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If an offset-axis damper is used to simplify manufacturing with continuous sealing profile, then manufacturing precision is improved, but reliability deteriorates when fire starts on the operating axis side causing deformation or jamming

Engineering Contradiction:
Improvecontinuous sealing profileVSAvoidfire protection capability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The damper is divided into two separate dampers (first damper and second damper) with their own independent operating axes and sealing profiles. Each damper handles fire protection from one direction, eliminating the reliability issue of offset-axis dampers while maintaining manufacturing simplicity through standardized designs.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The two dampers are positioned asymmetrically relative to the tunnel axis, with the first damper having its operating axis offset in one direction and the second damper offset in the opposite direction. This asymmetric arrangement allows each damper to effectively seal against fire from its respective side while maintaining continuous sealing coverage.

Inventive Principle:
Principle #4Asymmetry

2Device complexity

If a central pivot point is used for the damper, then the operating mechanism is simplified, but manufacturing precision deteriorates due to reversed sealing profiles on either side of the pivot

Engineering Contradiction:
Improveoperating mechanismVSAvoidsealing profile
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

Each damper uses an asymmetric offset-axis design where the operating axis is positioned away from the center, allowing the sealing profile to be continuous and uniform on one side of the axis. This eliminates the need for reversed sealing profiles while maintaining a relatively simple operating mechanism for each individual damper.

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 solution ensures the damper effectively maintains a fire-tight barrier by preventing deformation and dislodgment, even when exposed to high temperatures on one side, thereby containing the fire effectively.

Implementation Method 1

said first fusible element melting from a first defined maximum safety temperature, said first fusible element being configured to separate said mounting bracket and register by melting when the temperature at the shaft reaches said first defined maximum safety temperature

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP4678245A1Bi-directional fire protection flap with offset axis
Publication Date: 2026.01.14 SOLETANCHE FREYSSINET SAS
  • EP4678245A1 patent drawingFigure 1~2A
  • EP4678245A1 patent drawingFigure 2B~3
  • EP4678245A1 patent drawingFigure 4~5

AI summary

A control device for a butterfly damper of a fire damper, said butterfly damper being movable between an opening position of a passage in a damper tunnel and a closing position of said passage, said control device comprising an operating axis (120) of said damper offset with respect to a diameter of said damper, parallel to this diameter and out of the plane of said damper and comprising an operating motor in rotation of the operating axis (120), said axis (120) is secured to a face of the damper (110) by means of at least one fixing lug (130) provided with connecting parts (311, 312) with the damper comprising a first fusible element (311) melting from a first defined maximum safety temperature, said first fusible element (311) being configured to separate said fixing lug and the damper by melting when the temperature at the axis reaches said first defined maximum safety temperature.