Lateral Heat Sensor Placement in Combined Smoke Detector

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Solution Overview

Problem

Conventional combined heat and smoke detectors are thick due to the heat detecting means penetrating the dark chamber, limiting their thickness and increasing manufacturing costs, while also requiring separate design modifications for the body case.

Innovation Solution

The heat detecting means are arranged laterally to the dark chamber, allowing for reduced detector thickness, improved sensitivity, and the use of smoke detector components with minimal modifications, simplifying manufacturing and design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the heat detecting means penetrates the dark chamber with the leading end projected from the top surface, then the heat detection sensitivity is improved, but the detector thickness increases

Engineering Contradiction:
Improveheat detection sensitivityVSAvoiddetector thickness
Core Design Contradiction:
Measurement precisionVSLength of moving object

Solution Approach 1:

The heat detecting means are rearranged from a vertical penetration configuration (projecting from the top surface of the dark chamber) to a lateral arrangement (disposed beside the dark chamber). This dimensional change allows the heat detecting means to maintain exposure to ascending air currents while eliminating the need for vertical projection, thereby reducing detector thickness without sacrificing heat detection sensitivity

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If the heat detecting means penetrates the dark chamber with the leading end projected from the top surface, then the heat detection sensitivity is improved, but the manufacturing cost increases

Engineering Contradiction:
Improveheat detection sensitivityVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

By rearranging the heat detecting means from a penetrating vertical configuration to a lateral arrangement beside the dark chamber, the design simplifies manufacturing processes. This eliminates the need for complex modifications to the body case and dark chamber structure, allowing for easier assembly and reduced manufacturing costs while maintaining heat detection sensitivity through alternative exposure to ascending air currents

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Measurement precision

If the heat detecting means penetrates the dark chamber with the leading end projected from the top surface, then the heat detection sensitivity is improved, but the design complexity increases

Engineering Contradiction:
Improveheat detection sensitivityVSAvoiddesign complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The lateral arrangement of heat detecting means beside the dark chamber simplifies the overall detector design compared to the penetrating configuration. This arrangement eliminates the need for complex modifications to the body case structure and dark chamber geometry, reducing design complexity while maintaining the ability to detect heat through exposure to ascending air currents generated by fire

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 the detector's thickness, maintains sensitivity, lowers manufacturing costs, and unifies the design with smoke detectors, enabling effective heat and smoke detection while preventing damage to heat detecting components.

Implementation Method 1

capable of detecting fire through heat and smoke... detecting heat by means of a heat sensitive element such as thermistor... detect an ascending air current that occurs due to fire

Methodology Applied
Scientific EffectThermal convection: Convection

Implementation Method 2

detecting smoke by means of a light emitting device for emitting light and a light receiving device for receiving the light emitted from the light emitting device when the light is scattered by the smoke

Methodology Applied
Scientific EffectLight scattering: Scattering

Data Source

PatentEP2402920B1Combined heat and smoke detector
Publication Date: 2018.09.12 NITTAN CO LTD
  • EP2402920B1 patent drawingFigure 1
  • EP2402920B1 patent drawingFigure 2
  • EP2402920B1 patent drawingFigure 3~4

AI summary

A combined heat and smoke detector is provided. A housing is comprised of a body base and a body case covering an entire upper side of the body base. A circuit substrate is mounted on a top surface of the body base and disposed inside the housing. A smoke detecting portion configured to detect smoke flowing into a dark chamber and a plurality of heat detecting means for detecting heat are disposed inside the housing. The heat detecting means are arranged lateral to the dark chamber.