Flame Detector UV Sensor False Alarm Suppression
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Solution Overview
Problem
Conventional flame detectors using UV sensors are prone to false alarms due to non-flame sources of UV radiation, such as sunlight, and are costly, fragile, and require high voltages, limiting their effectiveness and practicality for residential use.
Innovation Solution
A flame detector design incorporating a UV sensor sensitive to solar UV radiation and a secondary sensor, such as a NIR or visible radiation sensor, with a controller that differentiates between strong and weak radiation sources to suppress false alarms, allowing for reduced manufacturing costs, improved durability, and lower voltage operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If UV sensors are used to detect flame radiation, then flame detection capability is improved, but false alarms increase due to non-flame UV sources like sunlight
Solution Approach 1:
The detection system is segmented into multiple independent sensors: a UV sensor for detecting UV radiation from flames, a visible radiation sensor for detecting visible light, and a NIR sensor for detecting near-infrared radiation. Each sensor monitors a specific portion of the electromagnetic spectrum, allowing the system to analyze the spectral composition of radiation sources and distinguish between flame and non-flame sources based on their characteristic radiation patterns.
Solution Approach 2:
The controller acts as an intermediary that receives signals from multiple sensors and processes them to make detection decisions. By comparing the relative intensities of UV, visible, and NIR radiation across different sensors, the controller can identify the spectral signature of flames versus sunlight or other non-flame UV sources, thereby reducing false alarms while maintaining flame detection accuracy.
2Reliability
If conventional UV sensors with sharp UV-C/UV-B cutoff are used, then false alarm suppression is improved, but device cost and fragility increase
Solution Approach 1:
The patent replaces expensive, fragile conventional UV sensors with thin film UV sensors that are more durable and cost-effective. These thin film sensors can be manufactured using deposition techniques and are less susceptible to damage, making the overall device more suitable for widespread residential installation while maintaining the ability to detect UV radiation from flames.
Solution Approach 2:
Instead of relying on a sharp UV-C/UV-B cutoff characteristic that requires expensive specialized sensors, the system changes the detection approach by using a UV sensor combined with visible and NIR sensors. The distinction between flame and non-flame sources is achieved through comparative analysis of radiation intensity across multiple wavelength ranges rather than through a single sensor's spectral cutoff property.
3Measurement precision
If UV phototubes are used for accurate flame detection, then detection precision is improved, but operational complexity and voltage requirements increase
Solution Approach 1:
The patent replaces conventional UV phototube technology with thin film UV sensor technology. Thin film sensors can be integrated into compact detector designs with lower voltage requirements and simpler operational characteristics. The combination of thin film UV, visible, and NIR sensors provides accurate flame detection through spectral analysis without the high voltage and operational complexity associated with traditional phototube-based systems.
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 solution effectively reduces false alarms caused by sunlight exposure, enhances durability, and lowers operational costs, making flame detectors more suitable for home use and other applications by accurately distinguishing between flame and non-flame radiation sources.
Implementation Method 1
Ultraviolet (UV) sensors can be particularly useful in detecting the radiation from flames in this type of application
Implementation Method 2
The secondary sensor can be a NIR sensor sensitive to NIR radiation
Implementation Method 3
The flame detector can further include a visible radiation sensor sensitive to visible radiation
Data Source
AI summary
A flame detector includes a UV sensor sensitive to solar UV radiation and a secondary sensor sensitive to non-UV radiation. A controller is operatively connected to the UV sensor and the secondary sensor to: signal an alarm in response to receiving input from the UV sensor indicative of a strong UV source and input from the secondary sensor indicative of a weak non-UV radiation source; and suppress an alarm in response to receiving a signal from the UV sensor indicative of a strong UV source and a signal from the secondary sensor indicative of a strong non-UV radiation source.