Smoke Detector Calibration Using a Chamberless Optical Block
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Solution Overview
Problem
Current smoke detector calibration methods using smoke boxes are cumbersome and time-consuming, lacking automation.
Innovation Solution
A chamberless optical detector calibration method using a calibration block with particles in a base material, positioned to overlap sensing volumes, to determine obscuration levels and adjust detector parameters for calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If smoke boxes are used for calibration, then calibration can be performed, but the process becomes cumbersome and time-consuming
Solution Approach 1:
The invention extracts the calibration function from the complex smoke box system and implements it using a simple optical block with known scattering properties. The optical block contains particles suspended in a transparent medium that simulate smoke scattering without requiring actual smoke generation, thus eliminating the time-consuming aspects of smoke box calibration while maintaining measurement precision.
Solution Approach 2:
The invention changes the calibration medium from actual smoke (complex, variable composition) to a controlled optical block with known particle concentration and scattering properties. By controlling parameters such as particle size, concentration, and material composition within the optical block, the calibration process achieves consistent results without the variability and time requirements of smoke-based methods.
2Measurement precision
If smoke boxes are used for calibration, then calibration can be performed, but the process lacks automation
Solution Approach 1:
The invention extracts the calibration function from the complex smoke box system and implements it using a simple optical block with known scattering properties. The optical block contains particles suspended in a transparent medium that simulate smoke scattering without requiring actual smoke generation, thus eliminating the time-consuming aspects of smoke box calibration while maintaining measurement precision.
Solution Approach 2:
The optical block is designed to be self-contained with known scattering characteristics, allowing the detector to calibrate itself by comparing measurements against the block's certified properties. This eliminates the need for manual intervention or complex automated smoke generation systems, achieving both accuracy and automation.
3Reliability
If multiple calibration points are determined using calibration blocks, then detector sensitivity is improved, but the calibration process complexity increases
Solution Approach 1:
The invention segments the calibration process into multiple discrete calibration blocks, each representing a specific obscuration level (e.g., 0%, 50%, 100%). Each block is independently characterized with known scattering properties, allowing the detector to establish multiple calibration points without requiring a single complex multi-functional calibration device. This segmentation simplifies the overall process while enabling comprehensive sensitivity calibration.
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
Facilitates rapid, automated calibration of smoke detectors, improving sensitivity and response time by ensuring accurate parameter adjustment.
Implementation Method 1
A calibration block is provided which includes a plurality of particles mixed within a base material such that the calibration block has a known obscuration. The calibration block is positioned to overlap a sensing volume defined between a light source and a light sensing device. Light from the light source scatters off the particles in the calibration block, and the light sensing device receives the scattered light to determine obscuration levels.
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A method of calibrating an optical detector includes positioning a calibration block relative to the optical detector and determining a first calibration point of the detector using the calibration block.