Bimetal Firestop Tongues for Early Opening Closure

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing fire protection solutions for openings in walls or ceilings, such as those used for pipes or cables, are expensive, require additional mechanical elements that occupy space, and do not effectively close openings until high temperatures are reached, which can lead to the pipes melting before closure occurs.

Innovation Solution

A fire protection element with a belt-shaped carrier and tongues made of bimetal, where a significant proportion of the tongues are formed of bimetal, allowing them to move at slightly elevated temperatures to mechanically close the opening and actively position fire protection material into the center of the opening, using a fire protection material like expandable graphite that expands when activated.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional intumescent materials are used, then fire protection is provided, but the activation temperature is too high causing pipes to melt before closure

Engineering Contradiction:

Improveactivation temperatureVSAvoidclosure effectiveness

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The fire protection element is segmented into multiple independent tongues that can move autonomously. Each tongue acts as an independent closure unit, allowing the system to function effectively even if individual tongues fail to activate properly.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the activation parameter from high temperature (conventional intumescent materials) to slightly elevated temperatures by using the bimetal effect. The bimetallic tongues change their physical state and curvature in response to temperature changes, enabling closure at lower temperatures before pipes melt.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If additional mechanical elements like springs are added, then early closure is achieved, but production cost and space requirements increase

Engineering Contradiction:

Improveclosure timingVSAvoidmechanical elements

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The bimetallic tongues are self-actuating elements that automatically respond to temperature changes without requiring external mechanical actuators like springs. The bimetallic structure itself serves as both the sensor and the actuator, eliminating the need for separate mechanical closing mechanisms.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The invention replaces complex mechanical spring systems with a thermal-mechanical bimetallic system. Instead of using springs that require mechanical activation, the bimetallic tongues directly convert thermal energy into mechanical movement, simplifying the overall system.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Temperature

If bimetallic tongues are used, then early closure at lower temperatures is achieved, but manufacturing complexity increases

Engineering Contradiction:

Improveactivation temperatureVSAvoidbimetal fabrication

Core Design Contradiction:

TemperatureVSEase of manufacture

Solution Approach 1:

The invention merges the carrier structure and the closing elements into a single integrated bimetallic component. The tongues are directly formed from the bimetallic material and attached to or integrated with the carrier, eliminating the need for separate manufacturing and assembly steps for different components.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The bimetallic carrier structure serves multiple functions: it provides the structural framework, contains the fire protection material, and generates the closing force through thermal activation. This multi-functionality reduces the number of separate components needed and simplifies manufacturing.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 bimetal tongues enable early closure of openings at lower temperatures, effectively preventing fire and smoke spread by mechanically closing the opening before the fire protection material activates, reducing material usage and installation complexity while ensuring stable closure.

Implementation Method 1

at least a significant proportion of the tongues being formed of a bimetal, which tongues can move in one direction under the effect of heat

Methodology Applied

Scientific EffectBimetallic effect: Bi-Metallic Strip

Implementation Method 2

using a fire protection material like expandable graphite that expands when activated

Methodology Applied

Scientific EffectIntumescent expansion: Intumescent Materials

Data Source

PatentUS20260063224A1Fire protection element having bimetal

Publication Date: 2026.03.05 HILTI AG

AI summary

A fire protection element can be used for sealing a combustible body, which penetrates an opening in a wall or ceiling, in the event of a fire. The fire protection element has a belt-shaped carrier from the edge of which tongues protrude transversely to the longitudinal direction of said carrier. The tongues are connected to the belt-shaped carrier, at least a significant proportion of the tongues being formed of a bimetal, and the tongues can move in one direction under the effect of heat. A fire protection material is applied to at least one side of the tongues. Furthermore, a method can be used for sealing a combustible body, which penetrates an opening in a wall or ceiling, in the event of a fire.