Fire Sensor Penetration Space Design for Smoke Sensitivity
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Solution Overview
Problem
Conventional fire sensors experience reduced smoke sensing sensitivity and delayed response due to the arrangement of the heat sensor, which obstructs the flow of smoke and scatters light, leading to hindered smoke flow and increased light scattering.
Innovation Solution
A fire sensor design with a penetration space defined by the housing of the light emitting or receiving unit, allowing the heat sensor to pass through a narrow region separate from the smoke sensing space, reducing the volume of the penetration space and minimizing obstruction of air flow, thereby enhancing smoke sensing sensitivity and response speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the heat sensor is arranged to extend through the smoke sensing space, then the heat sensor can detect temperature in the smoke sensing region, but the support member of the heat sensor hinders the flow of smoke toward the smoke sensing space and scatters light
Solution Approach 1:
The support member of the heat sensor is extracted from the smoke sensing space and relocated to a position on the outer periphery of the smoke sensing chamber. This allows the heat sensor to detect temperature in the smoke sensing region without its support member being present in the smoke sensing space, thereby eliminating the obstruction to smoke flow and light scattering caused by the support member.
Solution Approach 2:
The heat sensor is positioned in a different spatial dimension relative to the smoke sensing space. Instead of extending through the central region of the smoke sensing space, the heat sensor is arranged on the outer periphery, changing its spatial relationship with the smoke sensing region while still enabling heat detection.
2Object-affected harmful factors
If the light shield wall volume is increased to shield light, then light shielding is improved, but the flow of smoke from the gaps between the labyrinth walls toward the smoke sensing space is inhibited
Solution Approach 1:
The light shield wall is extracted from the smoke sensing space and relocated to a position on the outer periphery of the smoke sensing chamber. This allows the light shield wall to shield light effectively without occupying space within the smoke sensing region, thereby eliminating the inhibition of smoke flow toward the smoke sensing space.
Solution Approach 2:
The smoke sensing chamber is segmented into distinct functional regions: the smoke sensing space for detecting smoke particles, and the outer periphery region for housing the light shield wall and heat sensor. This segmentation allows each component to perform its function without interfering with the others.
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 reduced penetration space volume minimizes air flow obstruction and prevents smoke sensing sensitivity and response delay, allowing for more effective detection of smoke and heat.
Implementation Method 1
the light receiving unit receives the scattered light of the light emitting unit generated in the smoke sensing region by smokes introduced into the smoke sensing space
Implementation Method 2
a heat sensor, the smoke sensing space includes a smoke sensing region defined by a light emission zone extending from the light emitting unit and a light reception zone extending from the light receiving unit
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
A fire sensor (1) is provided with labyrinth walls (13) defining a smoke sensing space (A), and a light emitting unit (8), light receiving unit (9), and thermistor (3a) which are mounted on a circuit board (3). The light emitting unit (8) emits light onto the smoke sensing space (A), and the light receiving unit (9) senses smoke by receiving light scattered by smoke entering from the labyrinth walls (13), from the light emitted from the light emitting unit (8). The light emitting unit (8) forms a through-hole (15) passing through from the side of the circuit board (3) to an object detection space(room) within a peripheral wall (83) of a light emission platform portion (8b), forming together a penetration space (C) for the thermistor (3a) to pass though. As a result, the constituent volume of the penetration space (C) for the thermistor (3a) to pass through within the smoke sensing space (A) is reduced, reducing obstruction of airflow into the smoke sensing space (A), and suppressing decrease in smoke detector sensitivity and response rate.