Optical Clogged Filter Detector for High MERV HVAC Systems
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Solution Overview
Problem
Existing air filter detectors are inadequate for high MERV filters, which are more optically dense and require increased sensitivity to detect submicron particles, and often lack battery longevity, leading to inefficient HVAC system operation and maintenance challenges.
Innovation Solution
A clogged filter detector system comprising an optical transmitter and sensor with a processor, optimized for high MERV filters, using a transmitter and sensor misaligned with air flow to measure electromagnetic radiation through the filter, and featuring a controller that alternates between transmitting and dormant modes to extend battery life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a simple optical transmitter/sensor detector is used, then the device complexity and cost are reduced, but the measurement precision is insufficient for high MERV filters with higher optical density
Solution Approach 1:
The patent changes the optical parameters by using a laser diode transmitter emitting at a specific wavelength (650-950nm) and incorporating optical filters with specific transmission characteristics. The receiver uses a photodiode with matched spectral sensitivity. These parameter optimizations enable detection of high MERV filters without significantly increasing overall system complexity.
Solution Approach 2:
The patent replaces mechanical/differential pressure measurement systems with an optical detection system. Instead of using differential pressure switches that mechanically measure pressure differential across the filter, the invention uses optical transmission through the filter medium, substituting a mechanical measurement approach with an optical one that better suits high MERV filters.
2Reliability
If continuous monitoring is implemented, then the reliability of filter clogging detection is improved, but the use of energy by the detector increases
Solution Approach 1:
The patent implements periodic monitoring rather than continuous monitoring. The detector performs optical measurements at scheduled intervals, alternating between active measurement periods and dormant low-power periods. This periodic action maintains detection reliability while significantly reducing average energy consumption compared to continuous operation.
Solution Approach 2:
The patent makes the detector dynamically adjustable in its operational state, transitioning between active measurement mode and dormant low-power mode based on monitoring needs. This dynamic operation allows the system to adapt its energy consumption to actual monitoring requirements, maintaining reliability when needed while conserving battery power during extended intervals.
3Measurement precision
If the transmitter and sensor are aligned with air flow, then the ease of operation is improved, but the measurement precision is compromised due to optical density variations in the flow path
Solution Approach 1:
The patent applies local quality by measuring optical transmission at specific locations on the filter surface rather than requiring alignment with the overall air flow path. The transmitter and sensor are positioned to measure through specific regions of the filter media, allowing accurate local measurement of optical density regardless of the global flow direction. This enables precise measurement without requiring the transmitter-sensor axis to align with air flow.
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 system effectively detects clogging in high MERV filters, reducing energy consumption and extending filter life by providing timely maintenance notifications and optimizing battery usage.
Implementation Method 1
an optical transmitter adapted to transmit a beam of light or other electromagnetic radiation through the body of a filter (filter media) at least once
Implementation Method 2
a photo receiver/sensor positioned to detect the transmitted electromagnetic radiation once it passes through the filter media
Implementation Method 3
a photo receiver/sensor positioned to detect the transmitted electromagnetic radiation once it passes through the filter media
Data Source
AI summary
A clogged filter detector has a transmitter and a sensor which are held in place by a transmitter bracket and a sensor bracket, respectively. The transmitter emits a beam of electromagnetic radiation, and the sensor is positioned in the path of this beam at a point such that the beam travels through a filter between the transmitter and the sensor. The transmitter and sensor are mis-aligned with the air flow at the point where the beam contacts the filter. The transmitter alternates between a transmitting mode and a dormant mode, and the transmitter emits a plurality of electromagnetic pulses during each transmitting mode.