Smoke Detector Light Guide Integration

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Solution Overview

Problem

The placement of light-emitting diodes in smoke alarm devices creates aerodynamic turbulence, delaying the penetration of fire smoke into the smoke measuring cell and negatively impacting the device's triggering behavior, as per the DIN 14676 standard.

Innovation Solution

Integrating a light guide within rib- or web-shaped flow guidance components made of plastic to direct the light from the light source outside the housing, reducing turbulence and ensuring smooth smoke flow into the measuring cell.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a light-emitting diode is placed in the housing for optical signal display, then the device can provide visual signaling, but aerodynamic turbulence is generated that delays smoke penetration into the measuring cell

Engineering Contradiction:
Improvevisual signaling capabilityVSAvoidsmoke penetration time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The light source is extracted from the direct housing placement and its optical function is separated from its aerodynamic impact. The light guide extracts the light function while leaving the housing free of aerodynamic obstacles, thus removing the harmful effect while preserving the useful visual signaling function

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

A light guide is introduced as an intermediary element between the light source and the external environment. This mediator allows light to pass through while maintaining smooth airflow paths, eliminating the direct conflict between optical signaling and aerodynamic flow

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If components are placed in the housing, then the device structure is complete, but turbulence is generated that negatively impacts triggering behavior

Engineering Contradiction:
Improvecomponent integrationVSAvoidtriggering behavior consistency
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The housing structure is designed with locally optimized zones: areas with components have streamlined configurations, while critical flow paths maintain smooth, turbulence-free zones. This allows component integration while preserving flow quality in specific critical regions

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

Flow guidance components with curved, rib-shaped surfaces are used to guide smoke flow smoothly around components. The curved geometry eliminates sharp edges and corners that would generate turbulence, maintaining laminar flow and consistent triggering behavior

Inventive Principle:
Principle #14Spheroidality (Curvature)

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

This configuration reduces aerodynamic turbulence caused by optical signal displays, enhancing the smoke alarm's triggering behavior by ensuring timely and undisturbed smoke detection.

Implementation Method 1

at least one light guide (3) is integrated into the device for guiding the flow, which guides the light from the light source, preferably a light-emitting diode or a laser diode, to the outside of the housing

Methodology Applied
Scientific EffectLight guidance: Optical Fibre

Implementation Method 2

direct the fire smoke from the smoke inlet opening into the lead smoke measuring cell

Methodology Applied
Scientific EffectFlow guidance:

Data Source

PatentEP3267413B1Smoke warning device
Publication Date: 2022.10.05 ABB (SCHWEIZ) AG
  • EP3267413B1 patent drawingFigure 1~2

AI summary

The invention relates to a fire alarm detector comprising a housing (1), an acoustic signal generator (7), a light source (4), a plurality of inlet openings (5) arranged in the housing (1), a smoke measuring cell (6) for detecting smoke particles in incoming air, and at least one device arranged inside the housing for guiding the flow (2, 2') of the incoming air. At least one light guide (3) is integrated into the flow guide (2') device, which directs the light from the light source (4) to the outside of the housing.