Fire Detector Drift Compensation via Dynamic Sensitivity Modes
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Solution Overview
Problem
Fire detectors deteriorate over time due to dirt buildup, leading to increased sensitivity and a higher likelihood of false alarms, requiring frequent cleaning or replacement, especially in dirty environments, which is costly and inefficient.
Innovation Solution
A fire detector system with multiple sensitivity modes and a processor that adjusts the alarm threshold over time, switching to more sensitive modes as the drift compensation limit is approached, maintaining sensitivity and extending the detector's service life without compromising fire detection capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the alarm threshold is increased over time to compensate for detector deterioration, then the detector can operate longer without cleaning, but the detector eventually reaches a drift compensation limit where it can no longer resolve fire alarms
Solution Approach 1:
The patent applies dynamics by making the sensitivity mode adjustable and changeable over time. The detector dynamically switches between multiple sensitivity modes (first, second, third modes with increasing sensitivity) based on drift compensation needs, allowing the system to adapt its detection threshold rather than being fixed. This enables extended operation while maintaining reliable fire detection capability across different operational phases.
Solution Approach 2:
The patent implements parameter changes by modifying the alarm threshold parameter over time through drift compensation. The system changes the sensitivity parameter across multiple discrete modes, adjusting the detection threshold to account for detector deterioration. This allows the detector to maintain accurate fire alarm resolution throughout its extended service life by systematically adjusting the alarm point threshold parameter.
2Measurement precision
If the detector sensitivity is increased to detect fires more effectively, then fire detection capability improves, but the likelihood of false alarms increases
Solution Approach 1:
The system dynamically adjusts sensitivity based on operational phase rather than using a fixed high sensitivity setting. By transitioning through multiple sensitivity modes over time, the detector achieves high measurement precision when needed (in later operational phases with drift compensation) while maintaining lower false alarm rates during initial operation, thus resolving the contradiction between detection sensitivity and false alarm prevention.
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 approach extends the operational life of fire detectors by adjusting sensitivity modes to maintain effective fire detection while reducing the frequency of false alarms and maintenance costs, ensuring reliable operation without premature replacement.
Implementation Method 1
light from the light source will be reflected or scattered from the smoke particles. The reflected or scattered light will be detected by the light detector
Data Source
AI summary
A fire detector system comprises a fire detector unit;a sensor disposed in the fire detector unit and arranged to detect the characteristics of a fire and to generate an output signal indicative of the characteristics detected by the sensor; and a processor arranged to receive the output signal from the sensor and to generate afire alarm signal when the output signal exceeds an alarm point threshold; wherein the system is arranged to change the alarm point threshold over time to compensate for drift in the response of the detector unit; wherein the fire detector unit includes a first sensitivity mode with a first drift compensation limit and a second sensitivity mode with a second drift compensation limit, the second sensitivity mode being more sensitive than the first; and wherein, as the first alarm point threshold in the first sensitivity mode is approached or reached, the mode of the system is changed to the second sensitivity mode.