Fire Safety Door Pressure Equalization Mechanism

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Solution Overview

Problem

Fire protection doors in tunnels require significant force to open, especially when pressure differences exist, and existing solutions often rely on electrical power which is not always feasible.

Innovation Solution

The fire protection door features slits on the door leaf with a movable slider that is coupled to the door handle, allowing pressure equalization before the door is opened, and incorporates intumescent materials to expand and seal the slits in case of a fire, eliminating the need for electricity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the fire door is made solid and sealed to prevent fire and smoke spread, then fire resistance is improved, but the force required to open the door increases significantly especially under pressure difference

Engineering Contradiction:
Improvefire resistanceVSAvoidforce required to open door
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The door leaf is segmented with vertically extending slots that allow pressure equalization between the two sides of the door, reducing the pressure difference and thus the force required to open the door while maintaining fire resistance when the slots are covered

Inventive Principle:
Principle #1Segmentation

2Force

If an electric drive is used to extend a rod and create a gap for pressure equalization, then the force to open the door is reduced, but the device complexity and requirement for electrical power supply increases

Engineering Contradiction:
Improveforce to open doorVSAvoiddevice complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The slider is automatically actuated by the door handle mechanism itself when the handle is operated, eliminating the need for separate electric drives or power supplies. The mechanical movement of the handle directly moves the slider to cover or uncover the slots

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The function of the slider is merged with the existing door handle mechanism. The same mechanical action that operates the latch also operates the slider, combining two functions into one integrated mechanism

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If the slider covers the slots in closed position to maintain fire seal, then fire resistance is improved, but the pressure equalization function is lost

Engineering Contradiction:
Improvefire sealVSAvoidpressure difference
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The slider dynamically changes position between covering and uncovering the slots based on the door state. In closed position, the slider covers the slots to maintain fire seal. When the door handle is operated, the slider moves to uncover the slots, allowing pressure equalization before the door is opened

Inventive Principle:
Principle #15Dynamics

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

Reduces the force required to open the door by equalizing pressure mechanically and ensures the door remains functional without an electrical power supply, while also preventing fire spread through heat-expanding materials.

Implementation Method 1

The fire door is equipped with a slide that is movably arranged on the door leaf. In a slide closed position, the slide covers the door leaf slots. In a slide open position, the slide releases the door leaf slots

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP3892810B1Fire safety door
Publication Date: 2022.12.28 HODAPP
  • EP3892810B1 patent drawingFigure 1
  • EP3892810B1 patent drawingFigure 2
  • EP3892810B1 patent drawingFigure 3

AI summary

A fire door for closing door openings, preferably in tunnel tubes, is proposed, comprising a door leaf (2) movably arranged on a door frame (3), which is equipped with door leaf slots (7) designed as passage openings, a sliding mechanism (8) movably arranged on the door leaf (2), which covers the door leaf slots (7) in a sliding mechanism closed position and which exposes the door leaf slots (7) in a sliding mechanism open position, a latch arranged on the door leaf (2) which is movable from a latch opening position retracted into the door leaf (2) to a latch closing position projecting beyond the door leaf (2) and vice versa, and a door handle (5) arranged on the door leaf (2).which is coupled to the slide (8) and to the latch and which, when actuated, simultaneously moves the latch into the latch opening position and the slide (8) into the slide opening position.