Door Leaf Thermal Break Design for Fire Resistance
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Solution Overview
Problem
Existing door leaf designs in box cover configurations lack effective thermal insulation, rigidity, and cost-effectiveness, particularly in fire-resistant applications, with existing solutions either being expensive to produce or failing to achieve complete thermal separation between metal elements.
Innovation Solution
A door leaf design featuring a box cover construction with sheet metal elements that form a C-profile structure through complementary U-profiles and notches, filled with thermal insulation and reinforcement materials, ensuring indirect contact and complete thermal separation without touching, and using a method involving sheet metal folding and adhesive bonding for assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If sheet metal elements are used in box cover design, then structural strength is improved, but thermal insulation deteriorates due to direct contact between metal elements
Solution Approach 1:
A non-metallic intermediate element is introduced between the box plate and cover plate to prevent direct thermal contact. This intermediate element consists of a carrier structure with recesses that receive fire protection sealing strips, creating a thermal break while maintaining structural integrity and preventing heat transfer through the door leaf assembly.
Solution Approach 2:
The door leaf is divided into separate metal elements (box plate and cover plate) that do not directly contact each other. The intermediate element segments the thermal path, creating distinct zones separated by non-conductive materials, thereby reducing overall heat transfer while maintaining structural strength.
2Loss of energy
If thermal insulation material is inserted between metal elements, then thermal insulation is improved, but structural rigidity deteriorates due to gaps and indirect connection
Solution Approach 1:
The intermediate element combines a rigid carrier structure with fire protection sealing strips to create a composite assembly that provides both thermal insulation and structural support. The carrier structure maintains spatial relationships and prevents deformation, while the sealing strips provide thermal break functionality.
Solution Approach 2:
The intermediate element is designed with specific local features including recesses positioned at critical thermal bridge locations and fire protection sealing strips placed where thermal insulation is most needed. This localized approach maintains rigidity in structural areas while providing thermal insulation where required.
3Reliability
If complex intermediate elements with multiple components are used, then thermal insulation and fire protection are improved, but manufacturing cost and complexity increase
Solution Approach 1:
The intermediate element integrates multiple functions into a single assembly: the carrier structure provides structural support and positioning, while the fire protection sealing strips provide thermal insulation and fire resistance. This merging reduces the number of separate components and simplifies the assembly process compared to using separate elements for each function.
Solution Approach 2:
The intermediate element serves multiple purposes simultaneously: it acts as a spacer to maintain gaps between metal plates, provides thermal insulation through fire protection sealing strips, ensures structural stability through its carrier structure, and facilitates assembly through its geometric design with recesses and protrusions.
4Loss of energy
If gaps are created between metal elements for thermal separation, then thermal insulation is improved, but structural strength deteriorates due to reduced contact area
Solution Approach 1:
The intermediate element acts as a mediator that transmits mechanical loads while preventing thermal contact. The carrier structure of the intermediate element is designed to bear and distribute forces, allowing gaps to exist for thermal insulation purposes without compromising the overall structural strength of the door leaf assembly.
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 achieves high thermal insulation, increased rigidity, and cost-effective mass production while maintaining fire-resistant properties by ensuring complete thermal separation between metal elements, even under varying temperatures, without the need for additional stiffening elements.
Implementation Method 1
a filling material which conducts heat less well than the sheet metal is inserted into the side cavity
Implementation Method 2
The edge regions of the metal sheet elements have complementarily designed successions of projections and recesses seen in the longitudinal direction of the narrow end face, the projections of one sheet metal element engaging in the recesses of the other sheet metal element without contact
Data Source
AI summary
The leaf (10) has a vertical narrow front end (26) inserted into a door leaf cavity (30) of the door leaf. Side areas of sheet metal elements (12, 14) e.g. box metal sheets and lid metal sheets, are extended in a longitudinal direction of the narrow front end. A side cavity is filled with a filling material. The side cavity surrounds edge regions of the sheet metal elements, and is interconnected directly or indirectly through the filling material without touching the sheet metal elements. A reinforcing strip made of metal is embedded between thermal insulation stripes. An independent claim is also included for a method for manufacturing a door leaf.