Fiber Optic Smoke Detection Using Raman-Scattered Light

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Solution Overview

Problem

Conventional smoke detection systems experience delays in detecting fire due to smoke transport time in pipe networks and dilution of smoke with clean air, leading to insufficient detection of fire thresholds.

Innovation Solution

A fiber optic detection system utilizing a fiber optic cable with nodes and optical enhancement devices to analyze scattered light for the presence of smoke, employing Raman scattering and optical enhancement techniques to enhance sensitivity and accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If a pipe network with inlets is used to collect smoke, then smoke from multiple locations can be monitored, but smoke dilution occurs and detection threshold is not exceeded

Engineering Contradiction:
Improvemonitoring areaVSAvoidsmoke detection threshold
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The patent extracts the smoke detection function from the pipe network system and implements it directly at the smoke source location using a fiber optic node. This eliminates the dilution problem by detecting smoke at its origin rather than after it has traveled through and mixed with clean air in the pipe network.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a fiber optic node as an intermediary detection point between the smoke source and the central monitoring system. This node collects optical signals from the smoke plume and transmits them along the fiber optic cable to the remote monitoring location, enabling direct detection without relying on smoke transport through a pipe network.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If smoke is transported through a pipe network to a remote detector, then centralized monitoring is achieved, but detection delay occurs due to smoke transport time

Engineering Contradiction:
Improvecentralized monitoringVSAvoiddetection delay
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The fiber optic node serves as an intermediary that performs detection locally at the smoke source while maintaining connectivity to the centralized monitoring system through the fiber optic cable. This enables immediate detection at the source without requiring smoke to travel through a pipe network, eliminating transport-related delays.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical pipe network system with an optical fiber-based detection system. Instead of physically transporting smoke through pipes to a remote detector, the system uses fiber optic cables to transmit optical signals from the smoke plume to the monitoring location, achieving both rapid detection and centralized monitoring capability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If individual sensor units are positioned at each sensing location, then local detection accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvelocal detection accuracyVSAvoidsensor unit complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The fiber optic node is designed as a universal detection unit that can be deployed at multiple locations throughout the facility. Each node performs the same multi-functional detection and optical signal transmission, allowing the system to achieve high local detection accuracy at any location without requiring different types of complex sensor units for each position.

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 system enables rapid and accurate detection of smoke and fire by analyzing scattered light, reducing false positives and improving detection speed and precision.

Implementation Method 1

The at least one focusing element and at least one optical enhancement device of the discrimination assembly may be configured to cooperate to perform Raman scattering.

Methodology Applied
Scientific EffectRaman scattering: Scattering

Data Source

PatentEP3821415B1Enhanced robustness for high sensitivity fiber optic smoke detection
Publication Date: 2026.01.28 CARRIER CORP
  • EP3821415B1 patent drawingFigure 1
  • EP3821415B1 patent drawingFigure 1A
  • EP3821415B1 patent drawingFigure 2A~2B

AI summary

A detection system for measuring one or more conditions within a predetermined area includes a fiber optic cable including a first core for transmitting light to the ambient atmosphere adjacent a node and a second core for receiving scattered light from the ambient atmosphere adjacent the node. A discrimination assembly operably coupled to the first and second cores includes at least one focusing element and at least one optical enhancement device. The at least one optical enhancement device separates the scattered light received from the ambient atmosphere into a plurality of wavelengths. A control system operably coupled to the fiber optic cable receives the scattered light received from the ambient atmosphere. The scattered light received from the ambient atmosphere has a higher frequency than the light transmitted to the ambient atmosphere and only the scattered light having a desired wavelength is transmitted to the control system.