Polymer Optical Fiber Moisture Sensor for Distributed Monitoring
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Solution Overview
Problem
Current moisture measurement techniques in large structures, such as buildings and dams, are limited by the need for numerous point sensors, which are costly and prone to errors, and cannot detect moisture levels between sensor points, leading to incomplete monitoring.
Innovation Solution
A method using a polymer optical fiber sensor that provides distributed moisture measurement by analyzing backscatter data to determine scattering and attenuation profiles, allowing for spatially resolved monitoring with a single fiber, reducing the need for multiple sensors and enhancing accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If point sensors are used for moisture measurement in large structures, then moisture can be measured at specific locations, but the system becomes complex and costly due to the need for numerous individual sensors and wiring
Solution Approach 1:
The patent merges multiple point sensor functions into a single distributed fiber optic sensor system. The optical fiber acts as a continuous array of sensing points along its length, eliminating the need for numerous discrete sensors and their associated wiring infrastructure.
Solution Approach 2:
The optical fiber serves multiple functions simultaneously: it acts as both the sensing element and the signal transmission medium. The single fiber provides distributed moisture measurement along its entire length, replacing multiple specialized components with one multi-functional element.
2Measurement precision
If point sensors are used for moisture measurement, then discrete locations can be monitored, but critical moisture levels between sensor points remain undetected
Solution Approach 1:
The sensing function is segmented into continuous distributed measurement points along the fiber length. Instead of discrete sensor locations, the fiber provides measurement capability at every point along its path, creating a continuous profile of moisture distribution.
Solution Approach 2:
The measurement transitions from zero-dimensional point measurements to one-dimensional distributed measurements along the fiber length. This dimensional change enables continuous spatial resolution of moisture levels, capturing variations that would be missed by discrete point sensors.
3Reliability
If multiple point sensors are deployed for comprehensive monitoring, then coverage can be improved, but material and installation costs increase significantly
Solution Approach 1:
The patent combines multiple sensor functions into a single fiber optic cable that can be installed in one continuous operation. The fiber serves as both sensor and transmission medium, eliminating redundant components and reducing installation complexity and cost.
Solution Approach 2:
The system changes the fundamental parameter of measurement from discrete point values to continuous distributed values along the fiber length. This parameter change enables comprehensive monitoring coverage using a single sensor element rather than multiple sensors.
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
Enables continuous, cost-effective, and accurate moisture monitoring along extensive structures, reducing material and installation costs while improving detection sensitivity and reducing the risk of missed critical moisture levels.
Implementation Method 1
providing backscatter measurement data from a polymer optical fiber
Implementation Method 2
determining a moisture profile along the polymer optical fiber based on the relative scattering intensity profile
Data Source
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AI summary
The method involves providing rear dispersion-measuring data of an optical polymer fiber (120) that comprises polymethyl methacrylate as constituent, and determining a dispersion intensity profile along the polymer fiber from the measuring data. The determined intensity profile is compared with reference intensity for obtaining a relative dispersion intensity profile. A humidity profile along the polymer fiber is determined based on the relative dispersion intensity profile by an evaluation unit (150). A damping profile along the polymer fiber is determined from the measuring data. Independent claims are also included for the following: (1) a measuring device comprising an evaluation unit (2) a humidity sensor comprising an optical polymer fiber.