Moisture Sensor with Light Guide for Refrigerant Accuracy
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Solution Overview
Problem
Existing moisture sensors in refrigeration and air conditioning systems face challenges such as interference from contaminants, varying light reflectance, and temperature fluctuations, making them inaccurate for monitoring moisture levels in refrigerant working fluids.
Innovation Solution
A sensor system that uses a light source to transmit light through a color-changing moisture indicator to a color-sensing sensor, separated from the fluid flow, which generates an electrical signal and can adjust for light intensity variations, and provides an alarm when moisture thresholds are crossed, while allowing manual viewing of the indicator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a photodiode measures reflected light from a moisture indicator, then moisture level can be detected, but the measurement is affected by varying reflectance properties and light source fluctuations
Solution Approach 1:
The patent introduces a light guide as an intermediary component that channels light from the LED through the moisture indicator to the photodiode. This intermediary structure ensures consistent light coupling and reduces the impact of light source fluctuations and reflectance variations, thereby improving measurement reliability while maintaining detection accuracy
Solution Approach 2:
The system incorporates a feedback mechanism where the microcontroller monitors the photodiode output and adjusts the LED drive current to compensate for light source aging and temperature drift. This feedback loop maintains consistent illumination conditions, reducing measurement errors and improving long-term reliability
2Adaptability or versatility
If the sensor system is placed in a remote or hard-to-access location, then moisture monitoring can occur in situ, but visual observation becomes ineffective
Solution Approach 1:
The patent replaces the mechanical/visual inspection method with an electronic sensing system. The photodiode optically detects moisture indicator changes and converts them to electrical signals processed by a microcontroller, which then outputs digital readings or alarm signals. This substitution eliminates the need for direct visual observation, enabling reliable operation in remote locations while maintaining ease of operation through electronic readouts
3Adaptability or versatility
If contaminants are present in the working fluid, then the system operates in realistic conditions, but interference with reflected light measurement occurs
Solution Approach 1:
The light guide acts as an optical intermediary that confines and directs light through a controlled path between the LED, moisture indicator, and photodiode. This confinement reduces the impact of external contaminants in the working fluid on the light measurement, maintaining detection accuracy while allowing operation in realistic conditions with contaminant presence
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 accurately determines moisture levels with reduced interference, providing precise RGB color codes and alarm signals, and can indicate damage to the moisture indicator, improving monitoring efficiency and reliability.
Implementation Method 1
A light source is configured to transmit light through the moisture indicator to the light sensor
Implementation Method 2
a moisture indicator substrate that changes color when in the presence of moisture
Data Source
AI summary
A sensor system for sensing a moisture level of a working fluid includes a body housing a moisture indicator that changes color in the presence of moisture. The moisture indicator has a fixed position immersed in a path of fluid flow through the body. A light source is configured to transmit light through the moisture indicator to a color-sensing sensor of the sensor system. The sensor is separated from fluid flow through the system, and the system is configured to prevent external light from affecting the sensor. The moisture indicator is manually viewable where necessary. The sensor system also is configured to provide an electric signal corresponding to the color level of the moisture indicator, to generate an alarm signal with respect to a moisture level, to adjust for change in light intensity being sensed by the sensor, and to signify if the moisture indicator is damaged or has failed.