Self-Testing Fire Sensor Using Heated Wire Aerosol Generation
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Solution Overview
Problem
Existing fire alarm systems rely on manual testing of hazard sensing devices, which is time-consuming, expensive, and often fails to accurately determine the devices' ability to detect hazards within required timeframes, leading to potential missed faults and access issues in large facilities.
Innovation Solution
A self-testing hazard sensing device that uses a wire dipped in a material with a melting point greater than 70°C, heated by a controller to generate aerosol and carbon monoxide, allowing for continuous and accurate testing and recalibration without a liquid reservoir, enabling more realistic and controllable simulations of fire conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual testing of fire sensing devices is performed using pressurized aerosol and heat guns, then the testing process can be completed, but the testing is time-consuming, expensive, and disruptive to business operations
Solution Approach 1:
The fire sensing device performs self-testing by automatically generating test aerosol through an electrically heated wire coated with aerosol-generating material. The device's own heating element and airflow generator create the test conditions without requiring external manual intervention, thereby eliminating the time loss associated with manual testing while maintaining reliability assessment.
Solution Approach 2:
The wire is pre-coated with aerosol-generating material during manufacturing, preparing the device for self-testing capability in advance. This preliminary preparation allows the device to generate test aerosol on-demand without requiring manual application of coating materials during maintenance visits.
2Reliability
If manual testing is performed by maintenance engineers accessing devices in difficult areas, then testing can be conducted, but the process becomes expensive and disruptive to business
Solution Approach 1:
The self-testing capability eliminates the need for maintenance engineers to physically access and manually test each device. The device autonomously performs its own functional assessment, dramatically reducing maintenance labor costs and eliminating business disruption while ensuring reliability testing occurs for all devices including those in difficult-to-access locations.
3Reliability
If manual testing uses pressurized aerosol to saturate the chamber, then testing can be performed, but it may not accurately mimic fire characteristics and fail to determine detection ability within required timeframes
Solution Approach 1:
The electrically heated wire provides precise control over heating parameters (temperature, duration, power levels), allowing the generation of aerosol that more accurately mimics real fire characteristics. The controlled heating produces a realistic aerosol generation rate and composition that better represents actual fire conditions, enabling accurate measurement of detection timing and improving measurement precision for hazard detection ability assessment.
Solution Approach 2:
The patent replaces the mechanical pressurization system with an electrically heated wire that generates aerosol through controlled heating and evaporation. This substitution creates a more realistic simulation of fire aerosol generation, as natural fires produce aerosol through thermal processes rather than mechanical pressurization, thereby improving the accuracy of detection timing measurements.
4Reliability
If self-testing uses a liquid or wax reservoir to generate aerosol, then testing can be performed, but the device orientation is limited and leakage risks increase
Solution Approach 1:
The wire coated with aerosol-generating material undergoes phase transition from solid to gas through electrical heating, generating test aerosol without requiring a liquid or wax reservoir. This eliminates the need for orientation-specific reservoir structures and leakage prevention mechanisms, simplifying the device structure while maintaining reliable aerosol generation capability in any orientation.
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 solution reduces maintenance time, extends the service life of fire sensing devices, allows for continuous testing, and provides a more accurate assessment of their functionality, reducing the need for frequent replacements and minimizing environmental impact.
Implementation Method 1
a wire dipped in a material with a melting point greater than 70°C, heated by a controller to generate aerosol and carbon monoxide
Implementation Method 2
a wire dipped in a material with a melting point greater than 70°C, heated by a controller to generate aerosol
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
Devices, methods, and systems for a self-testing hazard sensing device are described herein. One device includes a sensor, a wire dipped in a material, a controller configured to provide a current to the wire to heat the material and generate aerosol and/or carbon monoxide, and an airflow generator configured to provide the aerosol and/or carbon monoxide to the sensor. The controller configured to determine whether the self-testing hazard sensing device is functioning properly using the aerosol and/or carbon monoxide provided to the sensor.