Duct Detector Self-Test via Labyrinth Light Path
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Solution Overview
Problem
Duct detectors in air handling systems are often installed in hard-to-reach locations, making functional testing inconvenient and hazardous, leading to infrequent or omitted testing due to accessibility issues.
Innovation Solution
A duct detector with a test light and labyrinth members that allows light to pass through, enabling a technician to test functionality without accessing the detector directly, using a control circuitry to generate an alarm signal if the light detector output exceeds a predefined trip level, indicating proper functioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If duct detectors are installed in elevated locations within ductwork, then monitoring coverage and system reliability are improved, but accessibility for functional testing deteriorates
Solution Approach 1:
The duct detector performs self-testing by generating its own test light signal and detecting it through the detector housing, eliminating the need for external testing equipment or technician access to the detector location. The detector serves both as the test signal source and the test signal detector.
Solution Approach 2:
The test light signal acts as an intermediary to transfer information about detector functionality. The light signal passes through the detector housing and labyrinth members to reach the detector, providing indirect testing without requiring physical access to the detector.
2Reliability
If manual smoke or particulate introduction is used for testing, then detector functionality can be verified, but system contamination and maintenance complexity increase
Solution Approach 1:
The patent replaces the mechanical approach of introducing smoke or particulate matter with an optical approach using a test light signal. This substitution eliminates contamination while verifying detector functionality through light detection rather than particulate detection.
Solution Approach 2:
The test light signal is a temporary, disposable test medium that is generated, used immediately for testing, and then discarded. Unlike smoke or particulate that may remain in the system, the light signal provides clean testing without residual contamination.
3Ease of operation
If technicians manually access elevated detector locations for testing, then functional testing can be performed, but safety risks and time consumption increase
Solution Approach 1:
The detector performs its own functional testing without requiring technician access to the elevated location. The self-testing capability eliminates safety hazards associated with technician access while maintaining regular testing schedules.
Solution Approach 2:
The detector is equipped with built-in testing capabilities that can be activated remotely or automatically, allowing testing to be performed in advance without requiring physical access. This preliminary action prevents the need for hazardous access during routine testing.
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 safe and convenient functional testing of duct detectors, reducing the risk of hazardous access and ensuring regular testing without introducing foreign particulate, thus maintaining system reliability.
Implementation Method 1
a plurality of labyrinth members defining at least a portion of the detector housing, wherein the labyrinth members allow light emitted by the test light to pass through the detector housing
Implementation Method 2
If the detector is functioning properly, an amount of light emitted by the test light will pass through the filter screen and labyrinth members of the detector assembly and will be detected by the light detector
Data Source
AI summary
A device and method for facilitating convenient functional testing of a duct detector is provided. The device includes a duct detector having a remote-controlled test light mounted in a housing thereof, and a detector chamber defined by a filter screen and a plurality of labyrinth members that allow light emitted by the test light to enter the detector chamber. A functional test of the duct detector can be conducted by activating the test light. If the detector is functioning properly, an amount of light emitted by the test light will be detected by the light detector, thereby simulating the presence of an excessive amount of particulate within the detector chamber. The light detector will then generate an output signal that will cause the actuation of alarms and/or the deactivation of a blower system, thereby indicating functionality of the duct detector.