Flow Shield and Restrictor for Stable Particle Measurement

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Solution Overview

Problem

Existing particle concentration measurement sensors face challenges in accurately capturing and measuring the concentration of particles, such as fire suppression agents, due to variations in particle sizes and turbulent gas flow, leading to inconsistent extraction and measurement accuracy.

Innovation Solution

A flow control device with a flow shield and restrictor system is employed to stabilize gas flow, ensuring laminar flow and consistent extraction of particle-laden gas, using shield openings and flow restrictors to maintain a near-constant extraction rate and minimize turbulence, thereby enhancing measurement accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a particle concentration measurement sensor is used to measure fire suppression agent concentration, then the measurement capability is provided, but turbulent gas flow causes inconsistent extraction and reduces measurement accuracy

Engineering Contradiction:
Improveparticle concentration measurement accuracyVSAvoidgas flow stability
Core Design Contradiction:
Measurement precisionVSStability of the object's composition

Solution Approach 1:

A flow control device is introduced as an intermediary component between the turbulent gas environment and the measurement sensor. This device includes a flow shield with multiple openings and a flow restrictor that mediates the gas flow, converting turbulent flow into laminar flow before the gas reaches the sensor, thereby ensuring consistent particle extraction and accurate measurement

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The flow control device changes the flow parameters of the gas by using a flow restrictor with specific orifice dimensions and a flow shield with controlled opening patterns. These parameter changes transform the gas flow from turbulent to laminar regime, ensuring stable and consistent particle concentration measurements

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If particles of different sizes are present in the gas, then the measurement sensor can detect various particles, but the extraction consistency varies due to size differences and turbulence

Engineering Contradiction:
Improveparticle size detection rangeVSAvoidextraction consistency
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The flow control device standardizes the flow parameters through the flow restrictor and flow shield, ensuring that particles of different sizes are extracted consistently under laminar flow conditions. The controlled flow parameters compensate for size-related variations, maintaining extraction consistency across different particle sizes

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If a flow control device with flow shield and restrictor is added, then gas flow is stabilized and measurement accuracy improves, but device complexity increases

Engineering Contradiction:
Improveparticle concentration measurement accuracyVSAvoidflow control structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The flow control device is segmented into distinct functional components: a flow shield with multiple openings and a flow restrictor with specific orifices. This segmentation allows each component to perform its specific function (flow distribution, flow restriction) while collectively achieving laminar flow and improved measurement accuracy without excessive complexity

Inventive Principle:
Principle #1Segmentation

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 flow control device ensures accurate and consistent measurement of particle concentration by stabilizing gas flow, allowing for precise determination of fire suppression agent concentration, even in turbulent environments.

Implementation Method 1

minimize turbulence

Methodology Applied
Scientific EffectTurbulence: Turbulence

Implementation Method 2

ensuring laminar flow

Methodology Applied
Scientific EffectLaminar flow: Laminar Flow

Implementation Method 3

The magnitude of the pressure drop across the flow restrictor far exceeds any dynamic pressure variations

Methodology Applied
Scientific EffectPressure drop: Pressure Drop

Data Source

PatentEP4080190B1Flow control device for particle concentration measurement sensor
Publication Date: 2025.08.27 KIDDE TECHNOLOGIES INC
  • EP4080190B1 patent drawingFigure 1
  • EP4080190B1 patent drawingFigure 2A~2B
  • EP4080190B1 patent drawingFigure 3A~3B

AI summary

A flow control device includes a flow shield defining a volume and a plurality of shield openings of the flow shield arranged such that gas entering the volume must pass through at least one of the plurality of shield openings. The flow control device also includes a flow restrictor to define an opening for the gas exiting the volume.