Smoke Detector Shielding Against Ambient Light False Alarms
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Solution Overview
Problem
Photoelectric smoke detectors often trigger false alarms due to ambient light from sources like germicidal disinfection systems, operating room lights, and UV curing systems, as the photoelectric receiver is not adequately shielded from external light sources, leading to incorrect detection of smoke particles.
Innovation Solution
A smoke detector shield configured to surround at least a majority portion of the smoke detector, using materials that block infrared, ultraviolet, and visible light, with a shroud and pole system that can be adjusted to fit various installations, and a tortuous air path to allow smoke entry while minimizing light transmission, providing a light-tight and airtight seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the photoelectric receiver is left exposed to ambient light, then the smoke detector can detect smoke particles, but false alarms are triggered by external light sources such as germicidal disinfection systems, operating room lights, and UV curing systems
Solution Approach 1:
A shield is introduced as an intermediary component between the ambient light sources and the photoelectric receiver. The shield selectively blocks harmful ambient light (including UV, visible, and infrared wavelengths from disinfection systems, operating lights, and curing systems) while allowing smoke particles to reach the detector through designated openings, thus mediating the interaction between light and the receiver to prevent false alarms
Solution Approach 2:
The shield is designed with non-uniform properties: it is opaque to light across multiple wavelengths to block ambient interference, but includes specific openings or transparent regions that allow smoke ingress. This local differentiation of quality (opaque vs. permeable regions) enables simultaneous protection from light and detection of smoke
2Reliability
If a shield is added to block ambient light, then false alarms are prevented, but the device complexity increases
Solution Approach 1:
The shield is designed to perform multiple functions simultaneously: it blocks UV light from germicidal systems, blocks visible light from operating lights, blocks infrared light from various sources, and maintains smoke particle ingress. This multi-functionality reduces the need for separate components for each wavelength, thereby limiting the increase in device complexity
Solution Approach 2:
The shield is implemented as a thin-walled structure made of material with appropriate optical properties. This thin-film approach provides effective light blocking across multiple wavelengths while minimizing the added volume, weight, and structural complexity of the overall device
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
Effectively prevents false tripping of smoke detectors by blocking ambient light, ensuring accurate detection of smoke particles while maintaining the functionality of the smoke detector during shielding, even in environments with high-intensity light emission devices.
Implementation Method 1
The shroud may comprise one or more materials that block that transmission of infrared light, ultraviolet light and/or visible light. In one embodiment, the material used to form the shroud may be specifically configured for blocking transmission of infrared light.
Implementation Method 2
The shroud may comprise one or more materials that block that transmission of infrared light, ultraviolet light and/or visible light.
Implementation Method 3
The shroud may comprise one or more materials that block that transmission of infrared light, ultraviolet light and/or visible light.
Implementation Method 4
Photoelectric smoke detectors use a light source and a photoelectric receiver to detect whether or not smoke is present in its ambient. Smoke is determined to be present when a change in the amount of light received at the photoelectric receiver exceeds a pre-determined value.
Data Source
AI summary
Smoke detector shields for blocking or minimizing the transmission of light therethrough and methods for use are provided. According to one embodiment, a method for shielding a smoke detector includes shielding at least a portion of a smoke detector operationally arranged within a room, and subsequently activating a light emission device arranged within the room, while shielding the smoke detector. In order to exclude light emission devices, which are commonly used within a room for lighting and/or communication purposes, the light emission device set forth in the method is configured for generating infrared light at a radiant intensity greater than approximately 1 W/sr, and/or ultraviolet light at a radiant intensity greater than approximately 1 W/sr, and/or visible light at a luminous flux greater than approximately 3000 lumens. Embodiments of smoke detector shields that prevent such light from penetrating the housing of a shielded smoke detector are provided herein.