Oblique-Leg Sensor Guard for Fire Detection Airflow

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Solution Overview

Problem

Fire sensors face challenges in optimizing airflow to detect environmental changes while protecting sensor elements from mechanical impact, leading to potential delays and inaccuracies in fire detection.

Innovation Solution

A sensor guard with oblique legs that funnel and redirect airflow towards the sensor element, minimizing deflection and drag, and featuring a guard ring and base design that enhances airflow and protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a sensor guard is used to protect the sensor element from mechanical impact, then protection against foreign objects is improved, but airflow to the sensor element is obstructed causing detection delays

Engineering Contradiction:

Improveprotection against mechanical impactVSAvoiddetection delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The sensor guard is divided into multiple discrete legs (typically 6 legs) arranged in a circular pattern around the sensor element. This segmentation allows airflow to pass through the gaps between legs while maintaining protective coverage, resolving the contradiction between protection and airflow.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The legs are positioned at specific radial distances from the sensor element and have optimized lengths and angles. The guard ring and base structure provide localized protection at critical areas while maintaining open pathways for airflow to reach the sensor element directly.

Inventive Principle:

Principle #3Local quality

2Reliability

If a sensor guard is used to protect the sensor element, then protection against foreign objects is improved, but airflow deflection and drag increase reducing detection accuracy

Engineering Contradiction:

Improveprotection against foreign objectsVSAvoiddetection accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The legs are arranged asymmetrically in terms of their angular positioning and radial distances, optimized to minimize airflow disruption. The guard ring and base structure create an asymmetric configuration that directs airflow smoothly around the sensor element rather than creating turbulent eddies.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The legs and guard ring form a curved, conical arrangement that guides airflow smoothly around the sensor element. This curved geometry reduces abrupt changes in flow direction, minimizing turbulence and drag while maintaining protective coverage.

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

Improves airflow to the sensor element, reducing detection delays and increasing accuracy by minimizing airflow obstruction and material interference, resulting in more consistent and rapid fire detection across orientations.

Implementation Method 1

The legs funnel and re-direct airflow towards the sensor element. This results in improved airflow near the sensor element.

Methodology Applied

Scientific EffectAerodynamic flow redirection:

Implementation Method 2

Heat fire sensors can trigger an alarm when the ambient temperature exceeds a threshold temperature and/or when the rate of temperature rise is indicative of fire.

Methodology Applied

Scientific EffectThermal detection:

Implementation Method 3

Another type of fire sensor is a smoke fire sensor that detects fire by measuring smoke.

Methodology Applied

Scientific EffectSmoke detection:

Data Source

PatentUS9830794B2Fire sensor having a sensor guard for heat and smoke detection applications

Publication Date: 2017.11.28 TYCO FIRE & SECURITY GMBH

AI summary

A sensor guard and method of using the sensor guard to protect a sensor element of a fire sensor. The sensor guard includes one or more legs that extend in a direction that is oblique to a central axis of the fire sensor. The fire sensor includes a housing and the sensor element, extending from the housing, for detecting an indication of fire. The sensor guard is mounted on the housing for protecting the sensor element.