Thermistor Protector Opening for Airflow and Contact Prevention

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Solution Overview

Problem

Existing detectors face challenges in improving the inflow characteristic of detection targets while preventing user contact with detection elements, as widening the protector opening risks damage to internal components.

Innovation Solution

A disaster prevention apparatus with a preventor, a projection protruding from the outer cover, partitions the opening to allow detection targets to flow while preventing contact objects from entering the detection element.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the opening portion of the protector is widened to improve the inflow characteristic of hot air current to the thermistor, then the inflow characteristic is improved, but the risk of user's finger entering and damaging the thermistor increases

Engineering Contradiction:
Improveinflow characteristicVSAvoidprotection of detection element
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The opening portion is segmented into multiple smaller openings by partition walls, allowing hot air to flow through while preventing fingers from reaching the thermistor. This segmentation resolves the contradiction by maintaining protective function while enabling detection target inflow.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The partition walls act as intermediary structures between the opening and the thermistor, blocking direct access while allowing heat transfer. This intermediary structure enables both protection and functional performance.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If the opening portion is made larger to improve detection target inflow, then the inflow characteristic improves, but the detection element becomes vulnerable to contact damage

Engineering Contradiction:
Improveinflow characteristicVSAvoidcontact damage risk
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

By dividing the opening into multiple smaller openings with partition walls, the design allows sufficient total area for hot air inflow while each individual opening remains too small to accommodate a finger, thus preventing contact damage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the opening structure serve different functions: the partition walls provide protection while the open spaces allow heat flow. This local differentiation of quality resolves the contradiction between protection and inflow.

Inventive Principle:
Principle #3Local quality

3Reliability

If the preventor projection is made higher to better prevent finger contact, then the protection capability improves, but the inflow characteristic of detection target may be hindered

Engineering Contradiction:
Improveprotection capabilityVSAvoidinflow characteristic
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The preventor projection height is optimized to provide sufficient protection against finger contact while maintaining adequate clearance for hot air flow. The local quality of the projection structure is tuned to balance protection and inflow requirements.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The preventor projection extends partially into the opening space - enough to block finger access but not so much as to obstruct hot air flow. This partial action resolves the contradiction by providing just sufficient protection while maintaining functional inflow.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP4239609B1Disaster prevention device
Publication Date: 2026.02.11 HOCHIKI CORP
  • EP4239609B1 patent drawingFigure 1~2
  • EP4239609B1 patent drawingFigure 3~4
  • EP4239609B1 patent drawingFigure 5~6

AI summary

There is provided a disaster prevention apparatus capable of preventing a contact object from coming into contact with a detection element while improving an inflow characteristic of a detection target with respect to the detection element. A disaster prevention apparatus includes: an outer cover 11; a thermistor 14 that detects a physical quantity of a detection target; a protective portion 12 that accommodates the thermistor 14, that is provided on the outer cover 11, and that has an opening portion 122 through which the detection target flows in and out with respect to the thermistor 14; and a prevention portion 13 that prevents a contact object from coming into contact with the thermistor 14, and that is provided in the opening portion 122. The prevention portion 13 is a projection. The prevention portion 13 protrudes from the outer cover 11 side, the prevention portion 13 is provided at a position close to a center of an edge portion of the opening portion 122, and an outer surface of the prevention portion 13 is curved.