Self-Calibrating Fire Sensor With Controlled Aerosol Calibration
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Solution Overview
Problem
Fire sensing devices in large facilities often degrade or become contaminated, leading to inaccurate fire detection and the need for frequent replacement, which results in waste and environmental impact, while current sensitivity testing methods are impractical and inaccurate.
Innovation Solution
A self-calibrating fire sensing device with an adjustable particle generator and variable airflow generator to create controlled aerosols, allowing for continuous self-testing, calibration, and recalibration of optical scatter properties, ensuring accurate fire detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If fire sensing devices are used for extended periods, then operational experience and detection capability improve, but component degradation and contamination occur leading to inaccurate detection
Solution Approach 1:
The device performs preliminary calibration actions by generating test aerosols and measuring scatter properties before actual fire detection is needed. This preliminary self-calibration compensates for component degradation and contamination, ensuring detection accuracy is maintained throughout the extended service life of the device
Solution Approach 2:
The fire sensing device performs self-calibration by generating its own test aerosols internally and measuring the scatter properties of these aerosols. This self-service capability allows the device to automatically compensate for its own component degradation and contamination without external intervention, resolving the contradiction between extended service life and maintained detection accuracy
2Measurement precision
If sensitivity testing is performed to ensure accurate detection, then detection precision improves, but testing complexity and resource requirements increase
Solution Approach 1:
The fire sensing device performs self-calibration by generating its own test aerosols internally and measuring the scatter properties of these aerosols. This self-service capability allows the device to automatically compensate for its own component degradation and contamination without external intervention, resolving the contradiction between extended service life and maintained detection accuracy
Solution Approach 2:
The patent extracts the calibration function from external testing equipment and integrates it directly into the fire sensing device itself. By taking out the aerosol generation and measurement capabilities and embedding them within the detector, the system achieves high measurement precision without the complexity of external sensitivity testing equipment
3Reliability
If smoke detectors are replaced after a fixed time period to ensure accuracy, then detection reliability is maintained, but unnecessary waste and environmental impact increase
Solution Approach 1:
The fire sensing device performs self-calibration by generating its own test aerosols internally and measuring the scatter properties of these aerosols. This self-service capability allows the device to automatically compensate for its own component degradation and contamination without external intervention, resolving the contradiction between extended service life and maintained detection accuracy
Solution Approach 2:
The system dynamically adjusts the calibration parameters by measuring the scatter properties of test aerosols and using this information to compensate for component degradation. This parameter change approach allows the device to maintain detection reliability throughout its extended service life without premature replacement, reducing waste and environmental impact
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 device extends the service life of fire sensing devices by maintaining accurate sensitivity, reducing maintenance time, and minimizing unnecessary replacements, thus reducing environmental waste.
Implementation Method 1
an adjustable particle generator and a variable airflow generator configured to generate aerosol having a particular particle size and optical scatter properties
Implementation Method 2
a first transmitter light-emitting diode (LED) configured to emit a first light that passes through the aerosol, a second transmitter LED configured to emit a second light that passes through the aerosol
Implementation Method 3
a photodiode configured to detect a scatter level of the first light that passes through the aerosol and detect a scatter level of the second light that passes through the aerosol
Data Source
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AI summary
Devices, methods, and systems for a self-calibrating fire sensing device are described herein. One device includes an adjustable particle generator and a variable airflow generator configured to generate aerosol having a particular particle size and optical scatter properties at a controllable density level, a first transmitter light-emitting diode (LED) configured to emit a first light that passes through the aerosol, a second transmitter LED configured to emit a second light that passes through the aerosol, a photodiode configured to detect a scatter level of the first light that passes through the aerosol and detect a scatter level of the second light that passes through the aerosol, and a controller configured to calibrate a gain of the photodiode based on the detected scatter level of the first light, the detected scatter level of the second light, and the controllable aerosol density level.